1
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Baum M, Dobler S. Fecal Deployment: An Alternative Way of Defensive Host Plant Cardenolide Use by Lilioceris merdigera Larvae. J Chem Ecol 2024; 50:63-70. [PMID: 38062246 PMCID: PMC10991028 DOI: 10.1007/s10886-023-01465-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2023] [Revised: 11/26/2023] [Accepted: 11/28/2023] [Indexed: 04/04/2024]
Abstract
The brilliant red Lilioceris merdigera (Coleoptera, Chrysomelidae) can spend its entire life cycle on the cardenolide-containing plant Convallaria majalis (lily of the valley) and forms stable populations on this host. Yet, in contrast to many other insects on cardenolide-containing plants L. merdigera does not sequester these plant toxins in the body but rather both adult beetles and larvae eliminate ingested cardenolides with the feces. Tracer feeding experiments showed that this holds true for radioactively labeled ouabain and digoxin, a highly polar and a rather apolar cardenolide. Both compounds or their derivatives are incorporated in the fecal shields of the larvae. The apolar digoxin, but not the polar ouabain, showed a deterrent effect on the generalist predatory ant Myrmica rubra, which occurs in the habitat of L. merdigera. The deterrent effect was detected for digoxin both in choice and feeding time assays. In a predator choice assay, a fecal shield derived from a diet of cardenolide-containing C. majalis offered L. merdigera larvae better protection from M. rubra than one derived from non-cardenolide Allium schoenoprasum (chives) or no fecal shield at all. Thus, we here present data suggesting a new way how insects may gain protection by feeding on cardenolide-containing plants.
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Affiliation(s)
- Michael Baum
- Molecular Evolutionary Biology, Institute of Zoology, Universität Hamburg, Martin-Luther-King-Platz 3, 20146, Hamburg, Germany.
- Chemistry Education Department, IPN, Leibniz Institute for Science and Mathematics Education, Olshausenstraße 62, 24118, Kiel, Germany.
| | - Susanne Dobler
- Molecular Evolutionary Biology, Institute of Zoology, Universität Hamburg, Martin-Luther-King-Platz 3, 20146, Hamburg, Germany
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2
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Suresh PS, Kumari S, Sahal D, Sharma U. Innate functions of natural products: A promising path for the identification of novel therapeutics. Eur J Med Chem 2023; 260:115748. [PMID: 37666044 DOI: 10.1016/j.ejmech.2023.115748] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2022] [Revised: 08/14/2023] [Accepted: 08/17/2023] [Indexed: 09/06/2023]
Abstract
In the course of evolution, living organisms have become well equipped with diverse natural products that serve important functions, including defence from biotic and abiotic stress, growth regulation, reproduction, metabolism, and epigenetic regulation. It seems to be the organism's ecological niche that influences the natural product's structural and functional diversity. Indeed, natural products constitute the nuts and bolts of molecular co-evolution and ecological relationships among different life forms. Since natural products in the form of specialized secondary metabolites exhibit biological functions via interactions with specific target proteins, they can provide a simultaneous glimpse of both new therapeutics and therapeutic targets in humans as well. In this review, we have discussed the innate role of natural products in the ecosystem and how this intrinsic role provides a futuristic opportunity to identify new drugs and therapeutic targets rapidly.
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Affiliation(s)
- Patil Shivprasad Suresh
- C-H Activation & Phytochemistry Lab, Chemical Technology Division, CSIR-Institute of Himalayan Bioresource Technology, Palampur, 176061, Himachal Pradesh, India
| | - Surekha Kumari
- C-H Activation & Phytochemistry Lab, Chemical Technology Division, CSIR-Institute of Himalayan Bioresource Technology, Palampur, 176061, Himachal Pradesh, India
| | - Dinkar Sahal
- Malaria Drug Discovery Laboratory, International Centre for Genetic Engineering and Biotechnology, New Delhi, 110067, India
| | - Upendra Sharma
- C-H Activation & Phytochemistry Lab, Chemical Technology Division, CSIR-Institute of Himalayan Bioresource Technology, Palampur, 176061, Himachal Pradesh, India.
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3
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Herbertz M, Dalla S, Wagschal V, Turjalei R, Heiser M, Dobler S. Coevolutionary escalation led to differentially adapted paralogs of an insect's Na,K-ATPase optimizing resistance to host plant toxins. Mol Ecol 2023. [PMID: 37296537 DOI: 10.1111/mec.17041] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2023] [Revised: 04/24/2023] [Accepted: 05/30/2023] [Indexed: 06/12/2023]
Abstract
Cardiac glycosides are chemical defence toxins known to fatally inhibit the Na,K-ATPase (NKA) throughout the animal kingdom. Several animals, however, have evolved target-site insensitivity through substitutions in the otherwise highly conserved cardiac glycoside binding pocket of the NKA. The large milkweed bug, Oncopeltus fasciatus, shares a long evolutionary history with cardiac glycoside containing plants that led to intricate adaptations. Most strikingly, several duplications of the bugs' NKA1α gene provided the opportunity for differential resistance-conferring substitutions and subsequent sub-functionalization of the enzymes. Here, we analysed cardiac glycoside resistance and ion pumping activity of nine functional NKA α/β-combinations of O. fasciatus expressed in cell culture. We tested the enzymes with two structurally distinct cardiac glycosides, calotropin, a host plant compound, and ouabain, a standard cardiac glycoside. The identity and number of known resistance-conferring substitutions in the cardiac glycoside binding site significantly impacted activity and toxin resistance in the three α-subunits. The β-subunits also influenced the enzymes' characteristics, yet to a lesser extent. Enzymes containing the more ancient αC-subunit were inhibited by both compounds but much more strongly by the host plant toxin calotropin than by ouabain. The sensitivity to calotropin was diminished in enzymes containing the more derived αB and αA, which were only marginally inhibited by both cardiac glycosides. This trend culminated in αAβ1 having higher resistance against calotropin than against ouabain. These results support the coevolutionary escalation of plant defences and herbivore tolerance mechanisms. The possession of multiple paralogs additionally mitigates pleiotropic effects by compromising between ion pumping activity and resistance.
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Affiliation(s)
- Marlena Herbertz
- Institute of Cell and Systems Biology of Animals, Molecular Evolutionary Biology, Universität Hamburg, Hamburg, Germany
| | - Safaa Dalla
- Institute of Cell and Systems Biology of Animals, Molecular Evolutionary Biology, Universität Hamburg, Hamburg, Germany
| | - Vera Wagschal
- Institute of Cell and Systems Biology of Animals, Molecular Evolutionary Biology, Universität Hamburg, Hamburg, Germany
| | - Rohin Turjalei
- Institute of Cell and Systems Biology of Animals, Molecular Evolutionary Biology, Universität Hamburg, Hamburg, Germany
| | - Marlies Heiser
- Institute of Cell and Systems Biology of Animals, Molecular Evolutionary Biology, Universität Hamburg, Hamburg, Germany
| | - Susanne Dobler
- Institute of Cell and Systems Biology of Animals, Molecular Evolutionary Biology, Universität Hamburg, Hamburg, Germany
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4
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Espinosa Del Alba L, Petschenka G. No physiological costs of dual sequestration of chemically different plant toxins in the milkweed bug Spilostethus saxatilis (Heteroptera: Lygaeidae). JOURNAL OF INSECT PHYSIOLOGY 2023; 147:104508. [PMID: 37011856 DOI: 10.1016/j.jinsphys.2023.104508] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/11/2022] [Revised: 02/06/2023] [Accepted: 03/31/2023] [Indexed: 06/02/2023]
Abstract
Many herbivorous insects not only cope with plant toxins but also sequester them as a defense against predators and parasitoids. Sequestration is a product of the evolutionary arms race between plants and herbivorous insects and has been hypothesized to incur physiological costs due to specific adaptations required. Contradictory evidence about these costs exists for insects sequestering only one class of toxin, but very little is known about the physiological implications for species sequestering structurally different classes of compounds. Spilostethus saxatilis is a milkweed bug belonging to the cardenolide-sequestering heteropteran subfamily Lygaeinae (Heteroptera: Lygaeidae) that has shifted to the colchicine-containing plant Colchicum autumnale, a resource of chemically unrelated alkaloids. Using feeding-assays on artificial diet and chemical analysis, we assessed whether S. saxatilis is still able to sequester cardenolides apart from colchicine and related metabolites (colchicoids), and tested the effect of (1) either a natural cardenolide concentration (using ouabain as a model compound) or a natural colchicine concentration, (2) an increased concentration of both toxins, and (3) seeds of either Asclepias syriaca (cardenolides) or C. autumnale (colchicoids) on a set of life-history traits. For comparison, we assessed the same life-history traits in the milkweed bug Oncopeltus fasciatus exposed to cardenolides only. Although cardenolides and colchicoids have different physiological targets (Na+/K+-ATPase vs tubulin) and thus require different resistance traits, chronic exposure and sequestration of both isolated toxins caused no physiological costs such as reduced growth, increased mortality, lower fertility, or shorter adult life span in S. saxatilis. Indeed, an increased performance was observed in O. fasciatus and an according trend was found in S. saxatilis when feeding on isolated ouabain and isolated colchicine, respectively. Positive effects were even more pronounced when insects were provided with natural toxic seeds (i.e. C. autumnale for S. saxatilis and A. syriaca for O. fasciatus), especially in O. fasciatus. Our findings suggest, that S. saxatilis can sequester two chemically unrelated classes of plant compounds at a cost-free level, and that colchicoids may even play a beneficial role in terms of fertility.
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Affiliation(s)
- Laura Espinosa Del Alba
- Department of Applied Entomology, Institute of Phytomedicine, University of Hohenheim, Otto-Sander Straße 5, 70599 Stuttgart, Germany
| | - Georg Petschenka
- Department of Applied Entomology, Institute of Phytomedicine, University of Hohenheim, Otto-Sander Straße 5, 70599 Stuttgart, Germany.
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5
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Agrawal AA, Hastings AP. Tissue-specific plant toxins and adaptation in a specialist root herbivore. Proc Natl Acad Sci U S A 2023; 120:e2302251120. [PMID: 37216531 PMCID: PMC10235950 DOI: 10.1073/pnas.2302251120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2023] [Accepted: 04/17/2023] [Indexed: 05/24/2023] Open
Abstract
In coevolution between plants and insects, reciprocal selection often leads to phenotype matching between chemical defense and herbivore offense. Nonetheless, it is not well understood whether distinct plant parts are differentially defended and how herbivores adapted to those parts cope with tissue-specific defense. Milkweed plants produce a diversity of cardenolide toxins and specialist herbivores have substitutions in their target enzyme (Na+/K+-ATPase), each playing a central role in milkweed-insect coevolution. The four-eyed milkweed beetle (Tetraopes tetrophthalmus) is an abundant toxin-sequestering herbivore that feeds exclusively on milkweed roots as larvae and less so on milkweed leaves as adults. Accordingly, we tested the tolerance of this beetle's Na+/K+-ATPase to cardenolide extracts from roots versus leaves of its main host (Asclepias syriaca), along with sequestered cardenolides from beetle tissues. We additionally purified and tested the inhibitory activity of dominant cardenolides from roots (syrioside) and leaves (glycosylated aspecioside). Tetraopes' enzyme was threefold more tolerant of root extracts and syrioside than leaf cardenolides. Nonetheless, beetle-sequestered cardenolides were more potent than those in roots, suggesting selective uptake or dependence on compartmentalization of toxins away from the beetle's enzymatic target. Because Tetraopes has two functionally validated amino acid substitutions in its Na+/K+-ATPase compared to the ancestral form in other insects, we compared its cardenolide tolerance to that of wild-type Drosophila and CRISPR-edited Drosophila with Tetraopes' Na+/K+-ATPase genotype. Those two amino acid substitutions accounted for >50% of Tetraopes' enhanced enzymatic tolerance of cardenolides. Thus, milkweed's tissue-specific expression of root toxins is matched by physiological adaptations in its specialist root herbivore.
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Affiliation(s)
- Anurag A. Agrawal
- Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, NY14853
- Department of Entomology, Cornell University, Ithaca, NY14853
| | - Amy P. Hastings
- Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, NY14853
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Heyworth HC, Pokharel P, Blount JD, Mitchell C, Petschenka G, Rowland HM. Antioxidant availability trades off with warning signals and toxin sequestration in the large milkweed bug ( Oncopeltus fasciatus). Ecol Evol 2023; 13:e9971. [PMID: 37038513 PMCID: PMC10082154 DOI: 10.1002/ece3.9971] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2022] [Revised: 03/13/2023] [Accepted: 03/17/2023] [Indexed: 04/12/2023] Open
Abstract
In some aposematic species the conspicuousness of an individual's warning signal and the concentration of its chemical defense are positively correlated. Several mechanisms have been proposed to explain this phenomenon, including resource allocation trade-offs where the same limiting resource is needed to produce both the warning signal and chemical defense. Here, the large milkweed bug (Oncopeltus fasciatus: Heteroptera, Lygaeinae) was used to test whether allocation of antioxidants, that can impart color, trade against their availability to prevent self-damage caused by toxin sequestration. We investigated if (i) the sequestration of cardenolides is associated with costs in the form of changes in oxidative state; and (ii) oxidative state can affect the capacity of individuals to produce warning signals. We reared milkweed bugs on artificial diets with increasing quantities of cardenolides and examined how this affected signal quality (brightness and chroma) across different instars. We then related the expression of warning colors to the quantity of sequestered cardenolides and indicators of oxidative state-oxidative lipid damage (malondialdehyde), and two antioxidants: total superoxide dismutase and total glutathione. Bugs that sequestered more cardenolides had significantly lower levels of the antioxidant glutathione, and bugs with less total glutathione had less luminant orange warning signals and reduced chroma of their black patches compared to bugs with more glutathione. Bugs that sequestered more cardenolides also had reduced red-green chroma of their black patches that was unrelated to oxidative state. Our results give tentative support for a physiological cost of sequestration in milkweed bugs and a mechanistic link between antioxidant availability, sequestration, and warning signals.
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Affiliation(s)
- H. Cecilia Heyworth
- Predators and Toxic Prey Research GroupMax Planck Institute for Chemical EcologyJenaGermany
- Centre for Ecology and Conservation, College of Life and Environmental SciencesUniversity of ExeterExeterUK
| | - Prayan Pokharel
- Department of Applied Entomology, Institute of PhytomedicineUniversity of HohenheimStuttgartGermany
| | - Jonathan D. Blount
- Centre for Ecology and Conservation, College of Life and Environmental SciencesUniversity of ExeterExeterUK
| | - Christopher Mitchell
- Centre for Ecology and Conservation, College of Life and Environmental SciencesUniversity of ExeterExeterUK
| | - Georg Petschenka
- Department of Applied Entomology, Institute of PhytomedicineUniversity of HohenheimStuttgartGermany
| | - Hannah M. Rowland
- Predators and Toxic Prey Research GroupMax Planck Institute for Chemical EcologyJenaGermany
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7
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Premachandran K, Srinivasan TS. Polyphagous insect Olepa sps . feeding on cardenolide rich Calotropis gigantea (L.) leaves and detoxification mechanism involving GST. Heliyon 2022; 8:e10596. [PMID: 36177231 PMCID: PMC9513775 DOI: 10.1016/j.heliyon.2022.e10596] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2022] [Revised: 08/14/2022] [Accepted: 09/06/2022] [Indexed: 11/28/2022] Open
Abstract
Cardenolides, a group of cardiac glycosides are potent inhibitors of Na+/K+ ATPase pump in mammals, animals including insects. Some insects can circumvent the toxicity of cardenolides by mechanisms like target site resistance and metabolic resistance resulting in enhanced tolerance or adaptation. In this paper, we report an intriguing observation of a polyphagous feeder feeding gregariously on the leaves of Calotropis gigantea (L.) without any apparent adverse effect. No choice feeding assay showed higher larval biomass and reduced number of days to develop on C. gigantea leaves compared to Ricinus and banana. We found the activity of GST higher in C. gigantea fed larva and HR LC-MS analysis of Olepa sps. revealed the presence of glutathione-strophanthidin conjugate in larval body tissue. In silico molecular simulation results confirmed strong interaction between delta variant GST and glutathione-strophanthidin complex. The sequestration site and cost benefit of glutathione-strophanthidin sequestration in body tissues of Olepa sps. needs further investigation.
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Affiliation(s)
- Krishnamanikumar Premachandran
- Centre for Climate Change Studies, International Research Centre, Sathyabama Institute of Science and Technology, Chennai 600119, Tamil Nadu, India
| | - Thanga Suja Srinivasan
- Centre for Climate Change Studies, International Research Centre, Sathyabama Institute of Science and Technology, Chennai 600119, Tamil Nadu, India
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8
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Functional evidence supports adaptive plant chemical defense along a geographical cline. Proc Natl Acad Sci U S A 2022; 119:e2205073119. [PMID: 35696564 PMCID: PMC9231628 DOI: 10.1073/pnas.2205073119] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Environmental clines in organismal defensive traits are usually attributed to stronger selection by enemies at lower latitudes or near the host's range center. Nonetheless, little functional evidence has supported this hypothesis, especially for coevolving plants and herbivores. We quantified cardenolide toxins in seeds of 24 populations of common milkweed (Asclepias syriaca) across 13 degrees of latitude, revealing a pattern of increasing cardenolide concentrations toward the host's range center. The unusual nitrogen-containing cardenolide labriformin was an exception and peaked at higher latitudes. Milkweed seeds are eaten by specialist lygaeid bugs that are even more tolerant of cardenolides than the monarch butterfly, concentrating most cardenolides (but not labriformin) from seeds into their bodies. Accordingly, whether cardenolides defend seeds against these specialist bugs is unclear. We demonstrate that Oncopeltus fasciatus (Lygaeidae) metabolized two major compounds (glycosylated aspecioside and labriformin) into distinct products that were sequestered without impairing growth. We next tested several isolated cardenolides in vitro on the physiological target of cardenolides (Na+/K+-ATPase); there was little variation among compounds in inhibition of an unadapted Na+/K+-ATPase, but tremendous variation in impacts on that of monarchs and Oncopeltus. Labriformin was the most inhibitive compound tested for both insects, but Oncopeltus had the greater advantage over monarchs in tolerating labriformin compared to other compounds. Three metabolized (and stored) cardenolides were less toxic than their parent compounds found in seeds. Our results suggest that a potent plant defense is evolving by natural selection along a geographical cline and targets specialist herbivores, but is met by insect tolerance, detoxification, and sequestration.
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9
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Herbertz M, Harder S, Schlüter H, Lohr C, Dobler S. Na,K-ATPase α1 and β-subunits show distinct localizations in the nervous tissue of the large milkweed bug. Cell Tissue Res 2022; 388:503-519. [PMID: 35332371 PMCID: PMC9110512 DOI: 10.1007/s00441-022-03580-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2021] [Accepted: 01/11/2022] [Indexed: 11/28/2022]
Abstract
The Na,K-ATPase (NKA) is an essential ion transporter and signaling molecule in all animal tissues and believed to consist at least one α and one ß-subunit to form a functional enzyme. In the large milkweed bug, Oncopeltus fasciatus, adaptation to dietary cardiac glycosides (CGs), which can fatally block the NKA, has resulted in gene duplications leading to four α1-subunits. These differ in sensitivity to CGs, but resistance trades off against ion pumping activity, thus influencing the α1-subunits’ suitability for specific tissues. Besides, O. fasciatus possesses four different ß-subunits that can alter the NKA's kinetics and should play an essential role in the formation of cellular junctions. Proteomic analyses revealed the distribution and composition of α1/ß-complexes in the nervous tissue of O. fasciatus. The highly CG-resistant, but less active α1B and the highly active, but less resistant α1C predominated in the nervous tissue and co-occurred with ß2 and ß3, partly forming larger complexes than just heterodimers. Immunohistochemical analyses provided a fine scale resolution of the subunits’ distribution in different morphological structures of the nervous tissue. This may suggest that α1 as well as ß-subunits occur in isolation without the other subunit, which contradicts the present understanding that the two types of subunits have to associate to form functional complexes. An isolated occurrence was especially prominent for ß3 and βx, the enigmatic fourth and N-terminally largely truncated ß-subunit. We hypothesize that dimerization of these ß-subunits plays a role in cell–cell contacts.
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Affiliation(s)
- Marlena Herbertz
- Institute of Cell and Systems Biology of Animals, Molecular Evolutionary Biology, Universität Hamburg, 20146, Hamburg, Germany.
| | - Sönke Harder
- Institute of Clinical Chemistry and Laboratory Medicine, University Medical Center Hamburg-Eppendorf, 20246, Hamburg, Germany
| | - Hartmut Schlüter
- Institute of Clinical Chemistry and Laboratory Medicine, University Medical Center Hamburg-Eppendorf, 20246, Hamburg, Germany
| | - Christian Lohr
- Institute of Cell and Systems Biology of Animals, Neurophysiology, Universität Hamburg, 20146, Hamburg, Germany
| | - Susanne Dobler
- Institute of Cell and Systems Biology of Animals, Molecular Evolutionary Biology, Universität Hamburg, 20146, Hamburg, Germany
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10
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Petschenka G, Halitschke R, Züst T, Roth A, Stiehler S, Tenbusch L, Hartwig C, Gámez JFM, Trusch R, Deckert J, Chalušová K, Vilcinskas A, Exnerová A. Sequestration of defenses against predators drives specialized host plant associations in preadapted milkweed bugs (Heteroptera: Lygaeinae). Am Nat 2022; 199:E211-E228. [DOI: 10.1086/719196] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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11
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Gourevitch EHZ, Shuker DM. Environmental Correlates of Sexual Signaling in the Heteroptera: A Prospective Study. INSECTS 2021; 12:insects12121079. [PMID: 34940167 PMCID: PMC8707444 DOI: 10.3390/insects12121079] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 10/08/2021] [Revised: 11/04/2021] [Accepted: 11/23/2021] [Indexed: 11/16/2022]
Abstract
Sexual selection is a major evolutionary process, shaping organisms in terms of success in competition for access to mates and their gametes. The study of sexual selection has provided rich empirical and theoretical literature addressing the ecological and evolutionary causes and consequences of competition for gametes. However, there remains a bias towards individual, species-specific studies, whilst broader, cross-species comparisons looking for wider-ranging patterns in sexual selection remain uncommon. For instance, we are still some ways from understanding why particular kinds of traits tend to evolve under sexual selection, and under what circumstances. Here we consider sexual selection in the Heteroptera, a sub-order of the Hemiptera, or true bugs. The latter is the largest of the hemimetabolous insect orders, whilst the Heteroptera itself comprises some 40,000-plus described species. We focus on four key sexual signaling modes found in the Heteroptera: chemical signals, acoustic signaling via stridulation, vibrational (substrate) signaling, and finally tactile signaling (antennation). We compare how these modes vary across broad habitat types and provide a review of each type of signal. We ask how we might move towards a more predictive theory of sexual selection, that links mechanisms and targets of sexual selection to various ecologies.
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12
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Villalona E, Ezray BD, Laveaga E, Agrawal AA, Ali JG, Hines HM. The role of toxic nectar secondary compounds in driving differential bumble bee preferences for milkweed flowers. Oecologia 2020; 193:619-630. [PMID: 32671460 DOI: 10.1007/s00442-020-04701-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2020] [Accepted: 06/30/2020] [Indexed: 11/26/2022]
Abstract
While morphological differences such as tongue length are often featured as drivers of pollinator floral preferences, differences in chemical detection and tolerance to secondary compounds may also play a role. We sought to better understand the role of secondary compounds in floral preference by examining visitation of milkweed flowers, which can contain toxic cardenolides in their nectar, by bumble bees (Bombus spp.), some of their most abundant and important pollinators. We examine bumble bee species visitation of common milkweed (Asclepias syriaca) compared to other flowers in the field and test whether observed preferences may be influenced by avoidance and tolerance of cardenolides, as measured by the cardenolide ouabain, in the lab. We reveal that common milkweed is visited predominantly by one bumble bee species, Bombus griseocollis, in a ratio much higher than the abundance of this species in the community. We confirmed the presence and toxicity of cardenolides in A. syriaca nectar. Lab experiments revealed that B. griseocollis, compared to the common bumble bees B. impatiens and B. bimaculatus, exhibit greater avoidance of cardenolides, but only at levels that start to induce illness, whereas the other species exhibit either no or reduced avoidance of cardenolides, resulting in illness and mortality in these bees. Toxicity experiments reveal that B. griseocollis also has a substantially higher tolerance for cardenolides than B. impatiens. Together, these results support a potential evolutionary association between B. griseocollis and milkweed that may involve increased ability to both detect and tolerate milkweed cardenolides.
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Affiliation(s)
- Eris Villalona
- Department of Biology, The Pennsylvania State University, University Park, PA, USA
| | - Briana D Ezray
- Department of Entomology, The Pennsylvania State University, University Park, PA, USA
- Department of Research Informatics and Publishing, The Pennsylvania State University Libraries, University Park, PA, USA
| | - Erica Laveaga
- Department of Biology, The Pennsylvania State University, University Park, PA, USA
| | - Anurag A Agrawal
- Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, NY, USA
| | - Jared G Ali
- Department of Entomology, The Pennsylvania State University, University Park, PA, USA
| | - Heather M Hines
- Department of Biology, The Pennsylvania State University, University Park, PA, USA.
- Department of Entomology, The Pennsylvania State University, University Park, PA, USA.
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13
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Havlikova M, Bosakova T, Petschenka G, Cabala R, Exnerova A, Bosakova Z. Analysis of defensive secretion of a milkweed bug Lygaeus equestris by 1D GC-MS and GC×GC-MS: sex differences and host-plant effect. Sci Rep 2020; 10:3092. [PMID: 32080314 PMCID: PMC7033152 DOI: 10.1038/s41598-020-60056-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2019] [Accepted: 02/03/2020] [Indexed: 11/09/2022] Open
Abstract
The composition of defensive secretion produced by metathoracic scent glands was analysed in males and females of the milkweed bug Lygaeus equestris (Heteroptera) using gas chromatography with mass spectrometric detection (GC-MS). The bugs were raised either on cardenolide-containing Adonis vernalis or on control sunflower seeds in order to determine whether the possibility to sequester cardenolides from their host plants would affect the composition of defensive scent-gland secretion. Profiles of the composition of defensive secretions of males and females raised on sunflower were closely similar, with predominant presence of (E)-2-octenal, (E)-2-octen-1-ol, decanal and 3-octen-1-ol acetate. The secretion of bugs raised on A. vernalis was more sexually dimorphic, and some chemicals e.g. (E,E)-2,4-hexadienyl acetate and 2-phenylethyl acetate were dominant in males, but absent in females. Compared to bugs from sunflower, the scent-gland secretion of bugs raised on A. vernalis was characterized by lower overall intensity of the peaks obtained for detected chemicals and by absence of some chemicals that have supposedly antipredatory function ((E)-2-hexenal, (E)-4-oxo-hex-2-enal, 2,4-octadienal). The results suggest that there might be a trade-off between the sequestration of defensive chemicals from host plants and their synthesis in metathoracic scent-glands.
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Affiliation(s)
- Martina Havlikova
- Department of Analytical Chemistry, Faculty of Science, Charles University, Prague, Czech Republic
| | - Tereza Bosakova
- Department of Analytical Chemistry, Faculty of Science, Charles University, Prague, Czech Republic
| | - Georg Petschenka
- Department of Insect Biotechnology, Justus-Liebig-University Giessen, Giessen, Germany
| | - Radomir Cabala
- Department of Analytical Chemistry, Faculty of Science, Charles University, Prague, Czech Republic.,Toxicology Department, Institute of Forensic Medicine and Toxicology, General University Hospital in Prague, Prague, Czech Republic
| | - Alice Exnerova
- Department of Zoology, Faculty of Science, Charles University, Prague, Czech Republic.
| | - Zuzana Bosakova
- Department of Analytical Chemistry, Faculty of Science, Charles University, Prague, Czech Republic.
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14
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Bramer C, Schweizer C, Dobler S. Cardenolide-defended milkweed bugs do not evoke learning inNephila senegalensisspiders. Ethology 2018. [DOI: 10.1111/eth.12757] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- Christiane Bramer
- Johann-Friedrich-Blumenbach-Institut; Georg-August-Universität; Göttingen Germany
- Institut für Zoologie; Universität Hamburg; Hamburg Germany
| | | | - Susanne Dobler
- Institut für Zoologie; Universität Hamburg; Hamburg Germany
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15
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Lohr JN, Meinzer F, Dalla S, Romey-Glüsing R, Dobler S. The function and evolutionary significance of a triplicated Na,K-ATPase gene in a toxin-specialized insect. BMC Evol Biol 2017; 17:256. [PMID: 29246105 PMCID: PMC5732401 DOI: 10.1186/s12862-017-1097-6] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2017] [Accepted: 11/27/2017] [Indexed: 01/27/2023] Open
Abstract
Background The Na,K-ATPase is a vital animal cell-membrane protein that maintains the cell’s resting potential, among other functions. Cardenolides, a group of potent plant toxins, bind to and inhibit this pump. The gene encoding the α-subunit of the pump has undergone duplication events in some insect species known to feed on plants containing cardenolides. Here we test the function of these duplicated gene copies in the cardenolide-adapted milkweed bug, Oncopeltus fasciatus, which has three known copies of the gene: α1A, α1B and α1C. Results Using RT-qPCR analyses we demonstrate that the α1C is highly expressed in neural tissue, where the pump is generally thought to be most important for neuron excitability. With the use of in vivo RNAi in adult bugs we found that α1C knockdowns suffered high mortality, where as α1A and α1B did not, supporting that α1C is most important for effective ion pumping. Next we show a role for α1A and α1B in the handling of cardenolides: expression results find that both copies are primarily expressed in the Malpighian tubules, the primary insect organ responsible for excretion, and when we injected either α1A or α1B knockdowns with cardenolides this proved fatal (whereas not in controls). Conclusions These results show that the Na,K-ATPα gene-copies have taken on diverse functions. Having multiple copies of this gene appears to have allowed the newly arisen duplicates to specialize on resistance to cardenolides, whereas the ancestral copy of the pump remains comparatively sensitive, but acts as a more efficient ion carrier. Interestingly both the α1A and α1B were required for cardenolide handling, suggesting that these two copies have separate and vital functions. Gene duplications of the Na,K-ATPase thus represent an excellent example of subfunctionalization in response to a new environmental challenge. Electronic supplementary material The online version of this article (10.1186/s12862-017-1097-6) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Jennifer N Lohr
- Universität Hamburg, Biozentrum Grindel, Zoologisches Institut, Martin-Luther-King Pl. 3, 20146, Hamburg, Germany. .,Department of Genetics, Evolution and Environment, Institute of Healthy Ageing, University College London, WC1E 6BT, London, UK.
| | - Fee Meinzer
- Universität Hamburg, Biozentrum Grindel, Zoologisches Institut, Martin-Luther-King Pl. 3, 20146, Hamburg, Germany
| | - Safaa Dalla
- Universität Hamburg, Biozentrum Grindel, Zoologisches Institut, Martin-Luther-King Pl. 3, 20146, Hamburg, Germany
| | - Renja Romey-Glüsing
- Universität Hamburg, Biozentrum Grindel, Zoologisches Institut, Martin-Luther-King Pl. 3, 20146, Hamburg, Germany
| | - Susanne Dobler
- Universität Hamburg, Biozentrum Grindel, Zoologisches Institut, Martin-Luther-King Pl. 3, 20146, Hamburg, Germany
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16
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Birnbaum SSL, Rinker DC, Gerardo NM, Abbot P. Transcriptional profile and differential fitness in a specialist milkweed insect across host plants varying in toxicity. Mol Ecol 2017; 26:6742-6761. [PMID: 29110382 DOI: 10.1111/mec.14401] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2017] [Accepted: 10/18/2017] [Indexed: 01/03/2023]
Abstract
Interactions between plants and herbivorous insects have been models for theories of specialization and co-evolution for over a century. Phytochemicals govern many aspects of these interactions and have fostered the evolution of adaptations by insects to tolerate or even specialize on plant defensive chemistry. While genomic approaches are providing new insights into the genes and mechanisms insect specialists employ to tolerate plant secondary metabolites, open questions remain about the evolution and conservation of insect counterdefences, how insects respond to the diversity defences mounted by their host plants, and the costs and benefits of resistance and tolerance to plant defences in natural ecological communities. Using a milkweed-specialist aphid (Aphis nerii) model, we test the effects of host plant species with increased toxicity, likely driven primarily by increased secondary metabolites, on aphid life history traits and whole-body gene expression. We show that more toxic plant species have a negative effect on aphid development and lifetime fecundity. When feeding on more toxic host plants with higher levels of secondary metabolites, aphids regulate a narrow, targeted set of genes, including those involved in canonical detoxification processes (e.g., cytochrome P450s, hydrolases, UDP-glucuronosyltransferases and ABC transporters). These results indicate that A. nerii marshal a variety of metabolic detoxification mechanisms to circumvent milkweed toxicity and facilitate host plant specialization, yet, despite these detoxification mechanisms, aphids experience reduced fitness when feeding on more toxic host plants. Disentangling how specialist insects respond to challenging host plants is a pivotal step in understanding the evolution of specialized diet breadths.
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Affiliation(s)
| | - David C Rinker
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, USA
| | - Nicole M Gerardo
- Department of Biology, O. Wayne Rollins Research Center, Emory University, Atlanta, GA, USA
| | - Patrick Abbot
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, USA
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17
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Rafter JL, Vendettuoli JF, Gonda-King L, Niesen D, Seeram NP, Rigsby CM, Preisser EL. Pretty Picky for a Generalist: Impacts of Toxicity and Nutritional Quality on Mantid Prey Processing. ENVIRONMENTAL ENTOMOLOGY 2017; 46:626-632. [PMID: 28334410 PMCID: PMC7263701 DOI: 10.1093/ee/nvx038] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/21/2016] [Indexed: 06/06/2023]
Abstract
Prey have evolved a number of defenses against predation, and predators have developed means of countering these protective measures. Although caterpillars of the monarch butterfly, Danaus plexippus L., are defended by cardenolides sequestered from their host plants, the Chinese mantid Tenodera sinensis Saussure guts the caterpillar before consuming the rest of the body. We hypothesized that this gutting behavior might be driven by the heterogeneous quality of prey tissue with respect to toxicity and/or nutrients. We conducted behavioral trials in which mantids were offered cardenolide-containing and cardenolide-free D. plexippus caterpillars and butterflies. In addition, we fed mantids starved and unstarved D. plexippus caterpillars from each cardenolide treatment and nontoxic Ostrinia nubilalis Hübner caterpillars. These trials were coupled with elemental analysis of the gut and body tissues of both D. plexippus caterpillars and corn borers. Cardenolides did not affect mantid behavior: mantids gutted both cardenolide-containing and cardenolide-free caterpillars. In contrast, mantids consumed both O. nubilalis and starved D. plexippus caterpillars entirely. Danaus plexippus body tissue has a lower C:N ratio than their gut contents, while O. nubilalis have similar ratios; gutting may reflect the mantid's ability to regulate nutrient uptake. Our results suggest that post-capture prey processing by mantids is likely driven by a sophisticated assessment of resource quality.
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Affiliation(s)
- Jamie L Rafter
- Department of Biological Sciences, University of Rhode Island, Kingston, RI 02881 ( ; ; ; ; )
- Department of Biology, Muskingum University, Concord, OH 43762
| | - Justin F Vendettuoli
- Department of Biological Sciences, University of Rhode Island, Kingston, RI 02881 (; ; ; ; )
| | - Liahna Gonda-King
- Department of Biological Sciences, University of Rhode Island, Kingston, RI 02881 (; ; ; ; )
| | - Daniel Niesen
- Department of Biomedical and Pharmaceutical Sciences, University of Rhode Island, Kingston, RI 02881 (; )
| | - Navindra P Seeram
- Department of Biomedical and Pharmaceutical Sciences, University of Rhode Island, Kingston, RI 02881 (; )
| | - Chad M Rigsby
- Department of Biological Sciences, University of Rhode Island, Kingston, RI 02881 (; ; ; ; )
| | - Evan L Preisser
- Department of Biological Sciences, University of Rhode Island, Kingston, RI 02881 (; ; ; ; )
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18
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Dalla S, Dobler S. Gene duplications circumvent trade-offs in enzyme function: Insect adaptation to toxic host plants. Evolution 2016; 70:2767-2777. [DOI: 10.1111/evo.13077] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2016] [Revised: 09/26/2016] [Accepted: 09/26/2016] [Indexed: 01/20/2023]
Affiliation(s)
- Safaa Dalla
- Molecular Evolutionary Biology, Zoological Institute, Biocenter Grindel; University of Hamburg; 20146 Hamburg Germany
| | - Susanne Dobler
- Molecular Evolutionary Biology, Zoological Institute, Biocenter Grindel; University of Hamburg; 20146 Hamburg Germany
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19
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Poiani SB, Costa-Leonardo AM. Dehiscent organs used for defensive behavior of kamikaze termites of the genus Ruptitermes (Termitidae, Apicotermitinae) are not glands. Micron 2016; 82:63-73. [PMID: 26774748 DOI: 10.1016/j.micron.2015.12.011] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2015] [Revised: 12/22/2015] [Accepted: 12/28/2015] [Indexed: 10/22/2022]
Abstract
During Isoptera evolution, the caste of soldiers disappeared in some Apicotermitinae termites as in the Neotropical Ruptitermes. Paired dorsolateral structures located between the metathorax and abdomen of foraging workers of Ruptitermes were previously denominated dehiscent glands, and are responsible for releasing an adhesive secretion that immobilizes enemies, causing their death. In this study, we investigated the morphology of dehiscent organs of workers of Ruptitermes reconditus, Ruptitermes xanthochiton, and Ruptitermes pitan and also second instar larvae of R. reconditus using light, laser scanning confocal, and transmission electron microscopy. Additionally, we performed a preliminary protein analysis using SDS-PAGE to further characterize the secretion of Ruptitermes dehiscent organs. Our results showed that the dehiscent organs do not exhibit the typical characteristics of the exocrine glandular cells class I, II or III of insects, suggesting that they constitute a new type of defensive organ. Thus, the denomination dehiscent gland was not used but dehiscent organ. Dehiscent organs in larvae are formed by fat body cells. In workers, dehiscent organs are composed by compact masses of cells that accumulate a defensive secretion and are poor in organelles related to the production of secretion. Since the dehiscent organs are not glands, we hypothesize that the dehiscent organs originate from larval fat body. The defensive secretion may have been produced at younger developmental stages of worker or the defensive compounds were absorbed from food and accumulated in the worker fat body. Histochemical techniques and SDS-PAGE revealed that the secretion of Ruptitermes dehiscent organs is constituted mainly by a protein of high molecular weight (200 kDa). In conclusion, the dehiscent organs are extremely different from the exocrine glands of termites and other insects described until now. In fact, they seem to be a specialized fat body that is peculiar and exclusive of Ruptitermes termites.
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Affiliation(s)
- Silvana B Poiani
- Departamento de Biologia, Instituto de Biociências de Rio Claro, Universidade Estadual Paulista-UNESP, Av. 24A, 1515, Bela Vista, 13.506-900 Rio Claro, SP, Brazil.
| | - Ana M Costa-Leonardo
- Departamento de Biologia, Instituto de Biociências de Rio Claro, Universidade Estadual Paulista-UNESP, Av. 24A, 1515, Bela Vista, 13.506-900 Rio Claro, SP, Brazil
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20
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Newcombe D, Hunt J, Mitchell C, Moore AJ. Maternal effects and maternal selection arising from variation in allocation of free amino acid to eggs. Ecol Evol 2015; 5:2397-410. [PMID: 26120429 PMCID: PMC4475372 DOI: 10.1002/ece3.1524] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2014] [Revised: 04/10/2015] [Accepted: 04/14/2015] [Indexed: 11/12/2022] Open
Abstract
Maternal provisioning can have profound effects on offspring phenotypes, or maternal effects, especially early in life. One ubiquitous form of provisioning is in the makeup of egg. However, only a few studies examine the role of specific egg constituents in maternal effects, especially as they relate to maternal selection (a standardized selection gradient reflecting the covariance between maternal traits and offspring fitness). Here, we report on the evolutionary consequences of differences in maternal acquisition and allocation of amino acids to eggs. We manipulated acquisition by varying maternal diet (milkweed or sunflower) in the large milkweed bug, Oncopeltus fasciatus. Variation in allocation was detected by examining two source populations with different evolutionary histories and life-history response to sunflower as food. We measured amino acids composition in eggs in this 2 × 2 design and found significant effects of source population and maternal diet on egg and nymph mass and of source population, maternal diet, and their interaction on amino acid composition of eggs. We measured significant linear and quadratic maternal selection on offspring mass associated with variation in amino acid allocation. Visualizing the performance surface along the major axes of nonlinear selection and plotting the mean amino acid profile of eggs from each treatment onto the surface revealed a saddle-shaped fitness surface. While maternal selection appears to have influenced how females allocate amino acids, this maternal effect did not evolve equally in the two populations. Furthermore, none of the population means coincided with peak performance. Thus, we found that the composition of free amino acids in eggs was due to variation in both acquisition and allocation, which had significant fitness effects and created selection. However, although there can be an evolutionary response to novel food resources, females may be constrained from reaching phenotypic optima with regard to allocation of free amino acids.
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Affiliation(s)
- Devi Newcombe
- Centre for Ecology and Conservation, University of Exeter Cornwall Campus, Penryn, TR10 9EZ, UK
| | - John Hunt
- Centre for Ecology and Conservation, University of Exeter Cornwall Campus, Penryn, TR10 9EZ, UK
| | - Christopher Mitchell
- Centre for Ecology and Conservation, University of Exeter Cornwall Campus, Penryn, TR10 9EZ, UK
| | - Allen J Moore
- Centre for Ecology and Conservation, University of Exeter Cornwall Campus, Penryn, TR10 9EZ, UK ; Department of Genetics, University of Georgia Athens, Georgia, 30602
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21
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Bramer C, Dobler S, Deckert J, Stemmer M, Petschenka G. Na+/K+-ATPase resistance and cardenolide sequestration: basal adaptations to host plant toxins in the milkweed bugs (Hemiptera: Lygaeidae: Lygaeinae). Proc Biol Sci 2015; 282:20142346. [PMID: 25808891 PMCID: PMC4389604 DOI: 10.1098/rspb.2014.2346] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2014] [Accepted: 03/03/2015] [Indexed: 11/12/2022] Open
Abstract
Despite sequestration of toxins being a common coevolutionary response to plant defence in phytophagous insects, the macroevolution of the traits involved is largely unaddressed. Using a phylogenetic approach comprising species from four continents, we analysed the ability to sequester toxic cardenolides in the hemipteran subfamily Lygaeinae, which is widely associated with cardenolide-producing Apocynaceae. In addition, we analysed cardenolide resistance of their Na(+)/K(+)-ATPases, the molecular target of cardenolides. Our data indicate that cardenolide sequestration and cardenolide-resistant Na(+)/K(+)-ATPase are basal adaptations in the Lygaeinae. In two species that shifted to non-apocynaceous hosts, the ability to sequester was secondarily reduced, yet Na(+)/K(+)-ATPase resistance was maintained. We suggest that both traits evolved together and represent major coevolutionary adaptations responsible for the evolutionary success of lygaeine bugs. Moreover, specialization on cardenolides was not an evolutionary dead end, but enabled this insect lineage to host shift to cardenolide-producing plants from distantly related families.
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Affiliation(s)
- Christiane Bramer
- Biozentrum Grindel, Martin-Luther-King-Platz 3, 20146 Hamburg, Germany
| | - Susanne Dobler
- Biozentrum Grindel, Martin-Luther-King-Platz 3, 20146 Hamburg, Germany
| | - Jürgen Deckert
- Museum für Naturkunde, Leibniz-Institut für Evolutions- und Biodiversitätsforschung, Invalidenstrasse 43, 10115 Berlin, Germany
| | | | - Georg Petschenka
- Biozentrum Grindel, Martin-Luther-King-Platz 3, 20146 Hamburg, Germany Department of Ecology and Evolutionary Biology, Cornell University, Corson Hall, Ithaca, NY 14853, USA
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22
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Newcombe D, Moore PJ, Moore AJ. The role of maternal effects in adaptation to different diets. Biol J Linn Soc Lond 2014. [DOI: 10.1111/bij.12408] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Affiliation(s)
- Devi Newcombe
- Centre for Ecology & Conservation; College of Life and Environmental Sciences; University of Exeter; Cornwall Campus Penryn TR10 9FE UK
| | - Patricia J. Moore
- Department of Entomology; University of Georgia; Athens GA 30602 USA
| | - Allen J. Moore
- Centre for Ecology & Conservation; College of Life and Environmental Sciences; University of Exeter; Cornwall Campus Penryn TR10 9FE UK
- Department of Genetics; University of Georgia; Athens GA 30602 USA
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23
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Martin RA, Lynch SP. Cardenolide content and thin-layer chromatography profiles of monarch butterflies,Danaus plexippus L., and their larval host-plant milkweed,Asclepias asperula subsp.Capricornu (woods.) woods., in north central Texas. J Chem Ecol 2013; 14:295-318. [PMID: 24277011 DOI: 10.1007/bf01022548] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/1986] [Accepted: 02/02/1987] [Indexed: 11/29/2022]
Abstract
This paper is the second in a series on cardenolide fingerprinting of monarch butterflies and their host-plant milkweeds in the eastern United States. Spectrophotometric determinations of the gross cardenolide content ofAsclepias asperula plants in north central Texas indicated wide variation ranging from 341 to 1616 μg/0.1 g dry weight. The mean plant cardenolide concentration (886 μg/0.1 g) is the highest for any milkweed species on which monarch cardenolide profiles have been produced. Forty-one butterflies reared individually on these plants contained a skewed distribution of cardenolide concentrations ranging from 231 to 515 μg/0. 1 g dry weight with a mean of 363μg/0.1 g. The uptake of cardenolide by the butterflies was independent of plant concentration, suggesting that saturation occurs in cardenolide sequestration by monarchs when feeding on cardenolide-rich host-plants. Female monarchs contained significantly greater mean cardenolide concentrations (339 μg/0.1 g) than did males (320 μg/0.1 g). The mean dry weight of the male butterflies (0.211 g) was significantly greater than the female mean (0.191) so that the mean total cardenolide contents of males (675 fig) and females (754 μg) were not significantly different. Butterfly size was not significantly correlated to butterfly cardenolide concentration when differences due to sex and individual host-plant concentration were removed. Thin-layer chrornatograms of 24 individual plant-butterfly pairs developed in two solvent systems resolved 22 individual spots in the plants and 15 in the butterflies.A. asperula plants appear to contain several relatively nonpolar cardenolides of the calotropagenin series which are metabolized to more polar derivatives in the butterflies. Quantitative evaluation of theR f values, spot intensities, and probabilities of occurrence in the chloroform-methanol-formamide TLC system produced a cardenolide fingerprint clearly distinct from those previously established for monarchs reared on otherAsclepias species. Our data support the use of fingerprints to make ecological predictions concerning larval host-plant utilization.A. asperula subsp.capricornu andA. viridis Walt, are the predominant early spring milkweeds throughout most of the south central United States. Cardenolide-rich monarchs reared on these two species may be instrumental in establishing and reinforcing visual avoidance of adults by naive predators throughout their spring and summer breeding cycle in eastern North America.
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Affiliation(s)
- R A Martin
- Department of Chemistry, Louisiana State University, 71115, Shreveport, Louisiana
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24
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Sapindaceae, cyanolipids, and bugs. J Chem Ecol 2013; 16:199-210. [PMID: 24264907 DOI: 10.1007/bf01021279] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/1989] [Accepted: 03/17/1989] [Indexed: 10/25/2022]
Abstract
Scentless plant bugs (Heteroptera: Rhopalidae) are so named because adults of the Serinethinae have vestigial metathoracic scent glands. Serinethines are seed predators of Sapindales, especially Sapindaceae that produce toxic cyanolipids. In two serinethine species whose ranges extend into the southern United States,Jadera haematoloma andJ. sanguinolenta, sequestration of host cyanolipids as glucosides renders these gregarious, aposematic insects unpalatable to a variety of predators. The blood glucoside profile and cyanogenesis ofJadera varies depending on the cyanolipid chemistry of hosts, and adults and larvae fed golden rain tree seeds (Koelreuteria paniculata) excrete the volatile lactone, 4-methyl-2(5H)-furanone, to which they are attracted.Jadera fed balloon vine seeds (Cardiospermum spp.) do not excrete the attractive lactone. Loss of the usual heteropteran defensive glands in serinethines may have coevolved with host specificity on toxic plants, and the orientation ofJadera to a volatile excretory product could be an adaptive response to save time.
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25
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Chemistryvis-à-vis maternalism in lace bugs (Heteroptera: Tingidae): Alarm pheromones and exudate defense inCorythucha andGargaphia species. J Chem Ecol 2013; 17:2307-22. [PMID: 24258608 DOI: 10.1007/bf00988010] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/1991] [Accepted: 07/23/1991] [Indexed: 10/25/2022]
Abstract
The hawthorn lace bug,Corythucha cydoniae, and the eggplant lace bug,Gargaphia solani, possess alarm pheromones that are produced in dorsal abdominal glands (DAGs). WhenG. solani nymphs are grasped, they emit secretion from both DAGs; the posterior DAG secretion alone elicits alarm, but the anterior DAG secretion may hasten the response. InC. cydoniae, the response is due to a synergism between the anterior and posterior DAG secretions, and nymphs are apparently unable to voluntarily release their DAG secretions; both DAGs must be ruptured for the pheromone to escape. The alarm pheromones are interspecifically active in patterns matching the intraspecific activities. Compounds identified from tingid DAG secretions that are involved in the alarm messages are: (E)2-hexenal, (E)-4-oxo-2-hexenal, acetaldehyde, geraniol, and linalool. A new natural product of unknown function (designated nerolidol aldehyde) was identified from the anterior DAG secretions of both species.
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26
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Sequestration of pyrrolizidine alkaloids in several arctiid moths (Lepidoptera: Arctiidae). J Chem Ecol 2013; 19:1889-903. [PMID: 24249366 DOI: 10.1007/bf00983794] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/1992] [Accepted: 04/06/1993] [Indexed: 10/25/2022]
Abstract
Sequestration of dietary pyrrolizidine alkaloids (PA) by larvae and adults of six European arctiid moth species (Spilosoma lubricipeda, Arctia caja, Phragmatobia fuliginosa, Callimorpha dominula, Diacrisia sannio, andTyria jacobaeae) was investigated for comparison with the well-studied Asian arctiidCreatonotos transiens. Larvae of all species metabolized free PA bases into the respectiveN-oxides. Only adults ofA. caja, P. fuliginosa, andS. lubricipeda, but not their larvae, converted dietary 7(S)-heliotrine to 7(R)-heliotrine, a direct precursor of a male pheromone in some arctiids, 7(R)-hydroxydanaidal. The larval integument figures as the main storage site for resorbed alkaloids; only minor amounts were found in other tissues. In addition, a significant amount of alkaloid is deposited in the cocoon ofArctia caja; only traces of alkaloids could be found in the meconium and the exuviae of this species. A substantial part of the alkaloids fed was degraded to unknown, nonalkaloidal products.
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27
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Dobler S, Rowell-Rahier M. Production of cardenolides versus sequestration of pyrrolizidine alkaloids in larvae ofOreina species (Coleoptera, Chrysomelidae). J Chem Ecol 2013; 20:555-68. [PMID: 24242111 DOI: 10.1007/bf02059597] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/1993] [Accepted: 10/18/1993] [Indexed: 10/25/2022]
Abstract
Adult leaf beetles of the genusOreina are known to be defended either by autogenously produced cardenolides or by pyrrolizidine alkaloids (PAs) sequestered from the food plant, or both. In this paper we analyze larvae of differentOreina species and show that the larvae contain the same defensive toxins as the adults in quantities similar to those released in the adults' secretion. Both classes of toxins are found in the body and hemolymph of the larvae, despite their different origins and later distribution in the adults. Larvae of sequestering species differed in their PA patterns, even though they fed on the same food plants. The concentration in first-instar larvae of a PA-sequestering species was similar to that in fourth-instar larvae. In all stages examined, the amount of PAs per larva did not greatly exceed the estimated uptake of one day. Eggs of two oviparous species contained large concentrations of the adult's toxins, while neonates of a sequestering larviparous species had no PAs.
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Affiliation(s)
- S Dobler
- Zoologisches Institut der Universität Basel, Rheinsprung 9, 4051, Basel, Switzerland
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28
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Holzinger F, Wink M. Mediation of cardiac glycoside insensitivity in the monarch butterfly (Danaus plexippus): Role of an amino acid substitution in the ouabain binding site of Na(+),K (+)-ATPase. J Chem Ecol 2013; 22:1921-37. [PMID: 24227116 DOI: 10.1007/bf02028512] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/1996] [Accepted: 05/16/1996] [Indexed: 12/01/2022]
Abstract
The Monarch butterfly (Danaus plexippus) sequesters cardiac glycosides (CG) for its chemical defense against predators. Larvae and adults of this butterfly are insensitive towards dietary cardiac glycosides, whereas other Lepidoptera are sensitive and intoxicated by ouabain. Ouabain inhibits Na(+),K(+)-ATPase by binding to its α-subunit. We have amplified and cloned the DNA-sequence encoding the respective ouabain binding site. Instead of the amino acid asparagine at position 122 in ouabain-sensitive insects, the Monarch has a histidine in the putative ouabain binding site, which consists of 12 amino acids. Starting with the CG-sensitive Na(+),K(+)-ATPase gene fromDrosophila, we converted pos. 122 to a histidine residue as inDanaus plexippus by site-directed mutagenesis. Human embryonic kidney cells (HEK) (which are sensitive to ouabain) were transfected with the mutated Na(+),K(+)-ATPase gene in a pSVDF-expression vector and showed a transient expression of the mutatedDrosophila Na(+),K(+)-ATPase. When treated with ouabain, the transfected cells tolerated ouabain at a concentration of 50 mM, whereas untransformed controls or controls transfected with the unmutatedDrosophila gene, showed a substantial mortality. This result implies that the asparagine to histidine exchange contributes to ouabain insensitivity in the Monarch. In two other CG-sequestering insects, e.g.,Danaus gilippus andSyntomeida epilais, the pattern of amino acid substitution differed, indicating that the Monarch has acquired this mutation independently during evolution.
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Affiliation(s)
- F Holzinger
- Institut für Pharmazeutische Biologie, Universität Heidelberg, Im Neuenheimer Feld 364, D-69120, Heidelberg, Germany
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Hotová Svádová K, Exnerová A, Kopečková M, Štys P. How Do Predators Learn to Recognize a Mimetic Complex: Experiments with Naive Great Tits and Aposematic Heteroptera. Ethology 2013. [DOI: 10.1111/eth.12121] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Affiliation(s)
- Kateřina Hotová Svádová
- Department of Zoology; Faculty of Science; Charles University in Prague; Prague; Czech Republic
| | - Alice Exnerová
- Department of Zoology; Faculty of Science; Charles University in Prague; Prague; Czech Republic
| | - Michala Kopečková
- Department of Zoology; Faculty of Science; Charles University in Prague; Prague; Czech Republic
| | - Pavel Štys
- Department of Zoology; Faculty of Science; Charles University in Prague; Prague; Czech Republic
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Burdfield-Steel ER, Dougherty LR, Smith LA, Collins LA, Shuker DM. Variation in social and sexual behaviour in four species of aposematic seed bugs (Hemiptera: Lygaeidae): the role of toxic and non-toxic food. Behav Processes 2013; 99:52-61. [PMID: 23796773 DOI: 10.1016/j.beproc.2013.06.006] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2013] [Revised: 06/10/2013] [Accepted: 06/12/2013] [Indexed: 11/28/2022]
Abstract
Understanding variation in social behaviour both within and among species continues to be a challenge. Evolutionary or ecological theory typically predicts the optimal behaviour for an animal under a given set of circumstances, yet the real world presents much greater variation in behaviour than predicted. This variation is apparent in many social and sexual interactions, including mate choice, and has led to a renewed focus on individual variation in behaviour. Here we explore within and among species variation in social behaviour in four species of aposematic seed bug (Lygaeidae: Hemiptera). These species are Müllerian mimics, with characteristic warning colouration advertising their chemical toxicity. We examine the role of diet in generating variation in two key behaviours: social aggregation of nymphs and mate choice. We test how behaviour varies with exposure to either milkweed (a source of defensive compounds) or sunflower (that provides no defence). We show that although the four species vary in their food preferences, and diet influences their life-history (as highlighted by body size), social aggregation and mate choice is relatively unaffected by diet. We discuss our findings in terms of the evolution of aposematism, the importance of automimicry, and the role of diet in generating behavioural variation.
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Affiliation(s)
- Emily R Burdfield-Steel
- School of Biology, University of St Andrews, Harold Mitchell Building, St Andrews KY14 7AU, United Kingdom.
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Abstract
Many predators quickly learn to avoid attacking aposematic prey. If the prey vary in toxicity, the predators may alternatively learn to capture and taste-sample prey carefully before ingesting or rejecting them (go-slow behaviour). An increase in prey toxicity is generally thought to decrease predation on prey populations. However, while prey with a higher toxin load are more harmful to ingest, they may also be easier to recognize and reject owing to greater distastefulness, which can facilitate a taste-sampling foraging strategy. Here, the classic diet model is used to study the separate effects of taste and toxicity on predator preferences. The taste-sampling process is modelled using signal detection theory. The model is applicable to automimicry and batesian mimicry. It shows that when the defensive toxin is sufficiently distasteful, a mimicry complex may be less profitable to the predator and better protected against predation if the models are moderately toxic than if they are highly toxic. Moreover, taste mimicry can reduce the profitability of the mimicry complex and increase protection against predation. The results are discussed in relation to the selection pressures acting on prey defences and the evolution of mimicry.
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Affiliation(s)
- Øistein Haugsten Holen
- Centre for Ecological and Evolutionary Synthesis (CEES), Department of Biology, University of Oslo, PO Box 1066 Blindern, 0316 Oslo, Norway.
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Community-wide convergent evolution in insect adaptation to toxic cardenolides by substitutions in the Na,K-ATPase. Proc Natl Acad Sci U S A 2012; 109:13040-5. [PMID: 22826239 DOI: 10.1073/pnas.1202111109] [Citation(s) in RCA: 180] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
The extent of convergent molecular evolution is largely unknown, yet is critical to understanding the genetics of adaptation. Target site insensitivity to cardenolides is a prime candidate for studying molecular convergence because herbivores in six orders of insects have specialized on these plant poisons, which gain their toxicity by blocking an essential transmembrane carrier, the sodium pump (Na,K-ATPase). We investigated gene sequences of the Na,K-ATPase α-subunit in 18 insects feeding on cardenolide-containing plants (spanning 15 genera and four orders) to screen for amino acid substitutions that might lower sensitivity to cardenolides. The replacement N122H that was previously shown to confer resistance in the monarch butterfly (Danaus plexippus) and Chrysochus leaf beetles was found in four additional species, Oncopeltus fasciatus and Lygaeus kalmii (Heteroptera, Lygaeidae), Labidomera clivicollis (Coleoptera, Chrysomelidae), and Liriomyza asclepiadis (Diptera, Agromyzidae). Thus, across 300 Myr of insect divergence, specialization on cardenolide-containing plants resulted in molecular convergence for an adaptation likely involved in coevolution. Our screen revealed a number of other substitutions connected to cardenolide binding in mammals. We confirmed that some of the particular substitutions provide resistance to cardenolides by introducing five distinct constructs of the Drosophila melanogaster gene into susceptible eucaryotic cells under an ouabain selection regime. These functional assays demonstrate that combined substitutions of Q(111) and N(122) are synergistic, with greater than twofold higher resistance than either substitution alone and >12-fold resistance over the wild type. Thus, even across deep phylogenetic branches, evolutionary degrees of freedom seem to be limited by physiological constraints, such that the same molecular substitutions confer adaptation.
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Agrawal AA, Petschenka G, Bingham RA, Weber MG, Rasmann S. Toxic cardenolides: chemical ecology and coevolution of specialized plant-herbivore interactions. THE NEW PHYTOLOGIST 2012; 194:28-45. [PMID: 22292897 DOI: 10.1111/j.1469-8137.2011.04049.x] [Citation(s) in RCA: 227] [Impact Index Per Article: 18.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Cardenolides are remarkable steroidal toxins that have become model systems, critical in the development of theories for chemical ecology and coevolution. Because cardenolides inhibit the ubiquitous and essential animal enzyme Na⁺/K⁺-ATPase, most insects that feed on cardenolide-containing plants are highly specialized. With a huge diversity of chemical forms, these secondary metabolites are sporadically distributed across 12 botanical families, but dominate the Apocynaceae where they are found in > 30 genera. Studies over the past decade have demonstrated patterns in the distribution of cardenolides among plant organs, including all tissue types, and across broad geographic gradients within and across species. Cardenolide production has a genetic basis and is subject to natural selection by herbivores. In addition, there is strong evidence for phenotypic plasticity, with the biotic and abiotic environment predictably impacting cardenolide production. Mounting evidence indicates a high degree of specificity in herbivore-induced cardenolides in Asclepias. While herbivores of cardenolide-containing plants often sequester the toxins, are aposematic, and possess several physiological adaptations (including target site insensitivity), there is strong evidence that these specialists are nonetheless negatively impacted by cardenolides. While reviewing both the mechanisms and evolutionary ecology of cardenolide-mediated interactions, we advance novel hypotheses and suggest directions for future work.
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Affiliation(s)
- Anurag A Agrawal
- Department of Ecology and Evolutionary Biology, and Department of Entomology, Cornell University, Ithaca, NY 14853, USA
| | - Georg Petschenka
- Biozentrum Grindel, Molekulare Evolutionsbiologie, Martin-Luther-King Platz 3, 20146 Hamburg, Germany
| | - Robin A Bingham
- Department of Natural and Environmental Sciences, Western State College of Colorado, Gunnison, CO 81231, USA
| | - Marjorie G Weber
- Department of Ecology and Evolutionary Biology, and Department of Entomology, Cornell University, Ithaca, NY 14853, USA
| | - Sergio Rasmann
- Department of Ecology and Evolution, Bâtiment Biophore, University of Lausanne, CH - 1015 Lausanne, Switzerland
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Dobler S, Petschenka G, Pankoke H. Coping with toxic plant compounds--the insect's perspective on iridoid glycosides and cardenolides. PHYTOCHEMISTRY 2011; 72:1593-1604. [PMID: 21620425 DOI: 10.1016/j.phytochem.2011.04.015] [Citation(s) in RCA: 116] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2010] [Revised: 03/30/2011] [Accepted: 04/20/2011] [Indexed: 05/27/2023]
Abstract
Specializing on host plants with toxic secondary compounds enforces specific adaptation in insect herbivores. In this review, we focus on two compound classes, iridoid glycosides and cardenolides, which can be found in the food plants of a large number of insect species that display various degrees of adaptation to them. These secondary compounds have very different modes of action: Iridoid glycosides are usually activated in the gut of the herbivores by β-glucosidases that may either stem from the food plant or be present in the gut as standard digestive enzymes. Upon cleaving, the unstable aglycone is released that unspecifically acts by crosslinking proteins and inhibiting enzymes. Cardenolides, on the other hand, are highly specific inhibitors of an essential ion carrier, the sodium pump. In insects exposed to both kinds of toxins, carriers either enabling the safe storage of the compounds away from the activating enzymes or excluding the toxins from sensitive tissues, play an important role that deserves further analysis. To avoid toxicity of iridoid glycosides, repression of activating enzymes emerges as a possible alternative strategy. Cardenolides, on the other hand, may lose their toxicity if their target site is modified and this strategy has evolved multiple times independently in cardenolide-adapted insects.
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Affiliation(s)
- Susanne Dobler
- Biocenter Grindel, Hamburg University, Martin-Luther-King Platz 3, 20146 Hamburg, Germany.
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36
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Agrawal AA, Salminen JP, Fishbein M. Phylogenetic trends in phenolic metabolism of milkweeds (Asclepias): evidence for escalation. Evolution 2008; 63:663-73. [PMID: 19220456 DOI: 10.1111/j.1558-5646.2008.00573.x] [Citation(s) in RCA: 94] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Although plant-defense theory has long predicted patterns of chemical defense across taxa, we know remarkably little about the evolution of defense, especially in the context of directional phylogenetic trends. Here we contrast the production of phenolics and cardenolides in 35 species of milkweeds (Asclepias and Gomphocarpus). Maximum-likelihood analyses of character evolution revealed three major patterns. First, consistent with the defense-escalation hypothesis, the diversification of the milkweeds was associated with a trend for increasing phenolic production; this pattern was reversed (a declining evolutionary trend) for cardenolides, toxins sequestered by specialist herbivores. Second, phylogenetically independent correlations existed among phenolic classes across species. For example, coumaric acid derivatives showed negatively correlated evolution with caffeic acid derivatives, and this was likely driven by the fact that the former are used as precursors for the latter. In contrast, coumaric acid derivatives were positively correlated with flavonoids, consistent with competition for the precursor p-coumaric acid. Finally, of the phenolic classes, only flavonoids showed correlated evolution (positive) with cardenolides, consistent with a physiological and evolutionary link between the two via malonate. Thus, this study presents a rigorous test of the defense-escalation hypothesis and a novel phylogenetic approach to understanding the long-term persistence of physiological constraints on secondary metabolism.
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Affiliation(s)
- Anurag A Agrawal
- Department of Ecology and Evolutionary Biology, and Center for a Sustainable Future, Cornell University, Corson Hall, Ithaca, New York 14853, USA
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Scudder GGE. Threads and serendipity in the life and research of an entomologist. ANNUAL REVIEW OF ENTOMOLOGY 2008; 53:1-17. [PMID: 17583998 DOI: 10.1146/annurev.ento.53.110106.153010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
This article presents an account of the development of Geoffrey Scudder's interest in entomology, with an emphasis on threads and serendipity. Early interests in Hemiptera, insect dispersal, evolution, and chemical ecology were followed by research on insect genitalia and seed bug systematics while at Oxford University. A faculty appointment in Canada led to research on water boatmen, water striders, cardenolides, faunistics, biodiversity, and habitat restoration. Since retirement, activities have diversified to include biodiversity mapping, conservation planning, and enhancing raised-bog integrity.
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Affiliation(s)
- Geoffrey G E Scudder
- Department of Zoology, University of British Columbia, British Columbia, Canada.
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Müller C, Agerbirk N, Olsen CE, Boevé JL, Schaffner U, Brakefield PM. Sequestration of host plant glucosinolates in the defensive hemolymph of the sawfly Athalia rosae. J Chem Ecol 2001; 27:2505-16. [PMID: 11789955 DOI: 10.1023/a:1013631616141] [Citation(s) in RCA: 76] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Interactions between insects and glucosinolate-containing plant species have been investigated for a long time. Although the glucosinolate-myrosinase system is believed to act as a defense mechanism against generalist herbivores and fungi, several specialist insects use these secondary metabolites for host plant finding and acceptance and can handle them physiologically. However, sequestration of glucosinolates in specialist herbivores has been less well studied. Larvae of the tumip sawfly Athalia rosae feed on several glucosinolate-containing plant species. When larvae are disturbed by antagonists, they release one or more small droplets of hemolymph from their integument. This "reflex bleeding" is used as a defense mechanism. Specific glucosinolate analysis, by conversion to desulfoglucosinolates and analysis of these by high-performance liquid chromatography coupled to diode array UV spectroscopy and mass spectrometry, revealed that larvae incorporate and concentrate the plant's characteristic glucosinolates from their hosts. Extracts of larvae that were reared on Sinapis alba contained sinalbin, even when the larvae were first starved for 22 hr and, thus, had empty guts. Hemolymph was analyzed from larvae that were reared on either S. alba, Brassica nigra, or Barbarea stricta. Leaves were analyzed from the same plants the larvae had fed on. Sinalbin (from S. alba), sinigrin (B. nigra), or glucobarbarin and glucobrassicin (B. stricta) were present in leaves in concentrations less than 1 micromol/g fresh weight, while the same glucosinolates could be detected in the larvae's hemolymph in concentrations between 10 and 31 micromol/g fresh weight, except that glucobrassicin was present only as a trace. In larval feces, only trace amounts of glucosinolates (sinalbin and sinigrin) could be detected. The glucosinolates were likewise found in freshly emerged adults, showing that the sequestered phytochemicals were transferred through the pupal stage.
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Affiliation(s)
- C Müller
- Institute of Evolutionary and Ecological Sciences, Leiden University, The Netherlands.
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40
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Dobler S. Evolutionary aspects of defense by recycled plant compounds in herbivorous insects. Basic Appl Ecol 2001. [DOI: 10.1078/1439-1791-00032] [Citation(s) in RCA: 78] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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Frick C, Wink M. Uptake and sequestration of ouabain and other cardiac glycosides inDanaus plexippus (Lepidoptera: Danaidae): Evidence for a carrier-mediated process. J Chem Ecol 1995; 21:557-75. [DOI: 10.1007/bf02033701] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/1994] [Accepted: 01/26/1995] [Indexed: 11/24/2022]
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Holzinger F, Frick C, Wink M. Molecular basis for the insensitivity of the Monarch (Danaus plexippus) to cardiac glycosides. FEBS Lett 1992; 314:477-80. [PMID: 1334851 DOI: 10.1016/0014-5793(92)81530-y] [Citation(s) in RCA: 80] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The Monarch (Danaus plexippus) sequesters cardiac glycosides for its chemical defence against predators. Larvae and adults of this butterfly are insensitive towards dietary cardiac glycosides, whereas other Lepidoptera, such as Manduca sexta and Creatonotos transiens are sensitive and intoxicated by ouabain. Ouabain inhibits the Na+,K(+)-ATPase by binding to its alpha-subunit. We have amplified and cloned the DNA sequence encoding the respective ouabain binding site. Instead of the amino acid asparagine at position 122 in ouabain-sensitive insects, the Monarch has a histidine in the putative ouabain binding site, which consists of about 12 amino acids. This change may explain the ouabain insensitivity.
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Affiliation(s)
- F Holzinger
- Institut für Pharmazeutische Biologie, Universität Heidelberg, Germany
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44
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Fate of iridoid glycosides in different life stages of the Buckeye,Junonia coenia (Lepidoptera: Nymphalidae). J Chem Ecol 1992; 18:817-31. [DOI: 10.1007/bf00988322] [Citation(s) in RCA: 68] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/1991] [Accepted: 01/22/1992] [Indexed: 10/26/2022]
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45
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Martin RA, Lynch SP, Brower LP, Malcolm SB, Van Hook T. Cardenolide content, emetic potency, and thin-layer chromatography profiles of monarch butterflies,Danaus plexippus, and their larval host-plant milkweed,Asclepias humistrata, in Florida. CHEMOECOLOGY 1992. [DOI: 10.1007/bf01261450] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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46
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Carrier-mediated uptake of digoxin by larvae of the cardenolide sequestering moth,Syntomeida epilais. Naturwissenschaften 1990. [DOI: 10.1007/bf01138391] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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47
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Wink M, Schneider D. Fate of plant-derived secondary metabolites in three moth species (Syntomis mogadorensis, Syntomeida epilais, andCreatonotos transiens). J Comp Physiol B 1990. [DOI: 10.1007/bf01075670] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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48
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Chemical defence in chewing and sucking insect herbivores: Plant-derived cardenolides in the monarch butterfly and oleander aphid. CHEMOECOLOGY 1990. [DOI: 10.1007/bf01240581] [Citation(s) in RCA: 49] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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49
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Gardner DR, Stermitz FR. Host plant utilization and iridoid glycoside sequestration byEuphydryas anicia (Lepidoptera: Nymphalidae). J Chem Ecol 1988; 14:2147-68. [DOI: 10.1007/bf01014022] [Citation(s) in RCA: 89] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/1987] [Accepted: 10/13/1987] [Indexed: 11/29/2022]
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50
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Brattsten LB. Enzymic adaptations in leaf-feeding insects to host-plant allelochemicals. J Chem Ecol 1988; 14:1919-39. [DOI: 10.1007/bf01013486] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/1987] [Accepted: 03/15/1988] [Indexed: 10/25/2022]
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