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VandenBrooks JM, Ford CF, Harrison JF. Responses to Alteration of Atmospheric Oxygen and Social Environment Suggest Trade-Offs among Growth Rate, Life Span, and Stress Susceptibility in Giant Mealworms ( Zophobas morio). Physiol Biochem Zool 2021; 93:358-368. [PMID: 32758057 DOI: 10.1086/710726] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Growth rate, development time, and response to environmental stressors vary tremendously across organisms, suggesting trade-offs that are affected by evolutionary or ecological factors, but such trade-offs are poorly understood. Prior studies using artificially selected lines of Manduca sexta suggest that insects with high growth rates, long development time, and large body size are more sensitive to hypoxic or hyperoxic stresses, such as reactive oxygen species (ROS) production, but the mechanisms and specific life-history associations remain unclear. Here, we manipulated the social environment to differentiate the effects of size, growth rate, and development time on oxygen sensitivity of the giant mealworm, Zophobas morio. Crowding reduced growth rates but yielded larger adults as a result of supernumerary molts and longer development times. The juvenile performance (growth rate, development time, adult mass) of crowd-reared mealworms was less sensitive to variation in atmospheric oxygen than it was for individually reared animals, consistent with the hypothesis that high growth rates are associated with increased sensitivity to ROS. Life span in normoxia was extended by crowd rearing, perhaps due to the larger size and/or increased resources of the larger adults. Life spans of crowd-reared animals were more negatively affected by hypoxia or hyperoxia than life spans of individually reared animals, possibly due to the longer total stress exposure of crowd-reared animals. These data suggest that animals with high growth rates experience a negative trade-off of performance with greater sensitivity to stress during the juvenile phase, while animals with long development times or life spans experience a negative trade-off of greater susceptibility of life span to environmental stress.
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Scott RL, Diao F, Silva V, Park S, Luan H, Ewer J, White BH. Non-canonical Eclosion Hormone-Expressing Cells Regulate Drosophila Ecdysis. iScience 2020; 23:101108. [PMID: 32408174 PMCID: PMC7225733 DOI: 10.1016/j.isci.2020.101108] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2020] [Revised: 04/15/2020] [Accepted: 04/22/2020] [Indexed: 11/26/2022] Open
Abstract
Eclosion hormone (EH) was originally identified as a brain-derived hormone capable of inducing the behavioral sequences required for molting across insect species. However, its role in this process (called ecdysis) has since been confounded by discrepancies in the effects of genetic and cellular manipulations of EH function in Drosophila. Although knock-out of the Eh gene results in severe ecdysis-associated deficits accompanied by nearly complete larval lethality, ablation of the only neurons known to express EH (i.e. Vm neurons) is only partially lethal and surviving adults emerge, albeit abnormally. Using new tools for sensitively detecting Eh gene expression, we show that EH is more widely expressed than previously thought, both within the nervous system and in somatic tissues, including trachea. Ablating all Eh-expressing cells has effects that closely match those of Eh gene knock-out; developmentally suppressing them severely disrupts eclosion. Our results thus clarify and extend the scope of EH action. Eh is expressed in non-neuronal peripheral tissues including trachea Eh expression is found in neurons other than the Vm neurons in pharate adults Non-Vm expression is essential for eclosion Non-neuronal Eh expression is required for normal larval ecdysis
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Affiliation(s)
- Robert L Scott
- Laboratory of Molecular Biology, National Institute of Mental Health, NIH, Bethesda, MD 20892, USA
| | - Fengqiu Diao
- Laboratory of Molecular Biology, National Institute of Mental Health, NIH, Bethesda, MD 20892, USA
| | - Valeria Silva
- Centro Interdisciplinario de Neurociencia, Universidad de Valparaiso, Playa Ancha, Valparaiso, CHILE
| | - Sanghoon Park
- Laboratory of Molecular Biology, National Institute of Mental Health, NIH, Bethesda, MD 20892, USA
| | - Haojiang Luan
- Laboratory of Molecular Biology, National Institute of Mental Health, NIH, Bethesda, MD 20892, USA
| | - John Ewer
- Centro Interdisciplinario de Neurociencia, Universidad de Valparaiso, Playa Ancha, Valparaiso, CHILE
| | - Benjamin H White
- Laboratory of Molecular Biology, National Institute of Mental Health, NIH, Bethesda, MD 20892, USA.
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Devrnja N, Kostić I, Lazarević J, Savić J, Ćalić D. Evaluation of tansy essential oil as a potential "green" alternative for gypsy moth control. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2020; 27:11958-11967. [PMID: 31983003 DOI: 10.1007/s11356-020-07825-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/12/2019] [Accepted: 01/21/2020] [Indexed: 05/27/2023]
Abstract
The development of "green" alternatives to chemical pesticides could play a crucial role in integrated pest management (IPM). Their use is considered either as a substitution for or in addition to hazardous synthetic products. We analysed the influence of three concentrations of tansy (Tanacetum vulgare L.) essential oil (EO), previously characterised by GC-MS, on the survival and moulting of the 2nd instar and the nutritional indices of the 4th instar gypsy moth (Lymantria dispar L.) larvae. In a residual contact toxicity assessment, the exposure to tansy EO caused low mortality (< 10%) while larval development was significantly slowed down, i.e., the percentage of larvae that moulted into the 3rd instar was reduced. On the other hand, when tansy EO was incorporated into the diet (digestive toxicity assay), high mortality and a lack of moulting after 120 h of eating were recorded for the highest applied concentration of EO. During 48 h of feeding on EO-supplemented food at concentrations of 0.5 and 1% (v/v), the relative growth rate (RGR) of the 4th instar larvae significantly decreased, which can be explained by a significant reduction of the relative consumption rate (RCR) and significantly or marginally significantly lower efficiency of conversion of ingested food into insect biomass (ECI). Although the RCR was also reduced with the lowest applied EO concentration (0.1%), the ECI was not affected which meant the RGR was as high as it was for the control larvae. ECI changes, when two higher EO concentrations were applied, were due to a reduction in the efficiency of conversion of digested food into biomass (ECD), while approximate digestibility was unaffected by the presence of EO in the food. Our results on the significant negative effects of tansy EO on gypsy moth larval survival, development time, and nutritional physiology suggest that it could be considered in future designs for botanical insecticides for gypsy moth control.
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Affiliation(s)
- Nina Devrnja
- Institute for Biological Research "Siniša Stanković"- National Institute of Republic of Serbia, University of Belgrade, Bulevar despota Stefana 142, Belgrade, 11060, Serbia.
| | - Igor Kostić
- Institute for Multidisciplinary Research, University of Belgrade, Kneza Višeslava 1, Belgrade, 11030, Serbia
| | - Jelica Lazarević
- Institute for Biological Research "Siniša Stanković"- National Institute of Republic of Serbia, University of Belgrade, Bulevar despota Stefana 142, Belgrade, 11060, Serbia
| | - Jelena Savić
- Institute for Biological Research "Siniša Stanković"- National Institute of Republic of Serbia, University of Belgrade, Bulevar despota Stefana 142, Belgrade, 11060, Serbia
| | - Dušica Ćalić
- Institute for Biological Research "Siniša Stanković"- National Institute of Republic of Serbia, University of Belgrade, Bulevar despota Stefana 142, Belgrade, 11060, Serbia
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Kivelä SM, Davis RB, Esperk T, Gotthard K, Mutanen M, Valdma D, Tammaru T. Comparative analysis of larval growth in Lepidoptera reveals instar‐level constraints. Funct Ecol 2020. [DOI: 10.1111/1365-2435.13556] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Affiliation(s)
- Sami M. Kivelä
- Department of Zoology Institute of Ecology and Earth Sciences University of Tartu Tartu Estonia
| | - Robert B. Davis
- Department of Zoology Institute of Ecology and Earth Sciences University of Tartu Tartu Estonia
| | - Toomas Esperk
- Department of Zoology Institute of Ecology and Earth Sciences University of Tartu Tartu Estonia
| | - Karl Gotthard
- Department of Zoology Stockholm University Stockholm Sweden
| | - Marko Mutanen
- Department of Ecology and Genetics University of Oulu Oulu Finland
| | - Daniel Valdma
- Department of Zoology Institute of Ecology and Earth Sciences University of Tartu Tartu Estonia
| | - Toomas Tammaru
- Department of Zoology Institute of Ecology and Earth Sciences University of Tartu Tartu Estonia
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Youngblood JP, da Silva CRB, Angilletta MJ, VandenBrooks JM. Oxygen Limitation Does Not Drive the Decreasing Heat Tolerance of Grasshoppers during Development. Physiol Biochem Zool 2019; 92:567-572. [PMID: 31567049 DOI: 10.1086/705439] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
Thermal physiology changes as organisms grow and develop, but we do not understand what causes these ontogenetic shifts. According to the theory of oxygen- and capacity-limited thermal tolerance, an organism's heat tolerance should change throughout ontogeny as its ability to deliver oxygen varies. As insects grow during an instar, their metabolic demand increases without a proportional increase in the size of tracheae that supply oxygen to the tissues. If oxygen delivery limits heat tolerance, the mismatch between supply and demand should make insects more susceptible to heat and hypoxia as they progress through an instar. We tested this hypothesis by measuring the heat tolerance of grasshoppers (Schistocerca americana) on the second and seventh days of the sixth instar, in either a normoxic or a hypoxic atmosphere (21% or 10% O2, respectively). As expected, heat tolerance decreased as grasshoppers grew larger. Yet contrary to expectation, hypoxia had no effect on heat tolerance across all stages and sizes. Although heat tolerance declines as grasshoppers grow, this pattern must stem from a mechanism other than oxygen limitation.
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Kivelä SM, Gotthard K, Lehmann P. Developmental plasticity in metabolism but not in energy reserve accumulation in a seasonally polyphenic butterfly. ACTA ACUST UNITED AC 2019; 222:jeb.202150. [PMID: 31138637 DOI: 10.1242/jeb.202150] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2019] [Accepted: 05/19/2019] [Indexed: 01/25/2023]
Abstract
The evolution of seasonal polyphenisms (discrete phenotypes in different annual generations) associated with alternative developmental pathways of diapause (overwintering) and direct development is favoured in temperate insects. Seasonal life history polyphenisms are common and include faster growth and development under direct development than in diapause. However, the physiological underpinnings of this difference remain poorly known despite its significance for understanding the evolution of polyphenisms. We measured respiration and metabolic rates through the penultimate and final larval instars in the butterfly Pieris napi and show that directly developing larvae grew and developed faster and had a higher metabolic rate than larvae entering pupal diapause. The metabolic divergence appeared only in the final instar, that is, after induction of the developmental pathway that takes place in the penultimate instar in P. napi. The accumulation of fat reserves during the final larval instar was similar under diapause and direct development, which was unexpected as diapause is predicted to select for exaggerated reserve accumulation. This suggests that overwinter survival in diapause does not require larger energy reserves than direct development, likely because of metabolic suppression in diapause pupae. The results, nevertheless, demonstrate that physiological changes coincide with the divergence of life histories between the alternative developmental pathways, thus elucidating the proximate basis of seasonal life history polyphenisms.
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Affiliation(s)
- Sami M Kivelä
- Department of Zoology, Institute of Ecology and Earth Sciences, University of Tartu, Vanemuise 46, EE-51014 Tartu, Estonia
| | - Karl Gotthard
- Department of Zoology, Stockholm University, SE-10691 Stockholm, Sweden
| | - Philipp Lehmann
- Department of Zoology, Stockholm University, SE-10691 Stockholm, Sweden
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Lundquist TA, Kittilson JD, Ahsan R, Greenlee KJ. The effect of within-instar development on tracheal diameter and hypoxia-inducible factors α and β in the tobacco hornworm, Manduca sexta. JOURNAL OF INSECT PHYSIOLOGY 2018; 106:199-208. [PMID: 29246704 PMCID: PMC5960420 DOI: 10.1016/j.jinsphys.2017.12.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/29/2017] [Revised: 12/04/2017] [Accepted: 12/06/2017] [Indexed: 05/10/2023]
Abstract
As insects grow within an instar, body mass increases, often more than doubling. The increase in mass causes an increase in metabolic rate and hence oxygen demand. However, the insect tracheal system is hypothesized to increase only after molting and may be compressed as tissues grow within an instar. The increase in oxygen demand in the face of a potentially fixed or decreasing supply could result in hypoxia as insects near the end of an instar. To test these hypotheses, we first used synchrotron X-ray imaging to determine how diameters of large tracheae change within an instar and after molting to the next instar in the tobacco hornworm, Manduca sexta. Large tracheae did not increase in diameter within the first, second, third, and fourth instars, but increased upon molting. To determine if insects are hypoxic at the end of instars, we used the presence of hypoxia-inducible factors (HIFs) as an index. HIF-α and HIF-β dimerize in hypoxia and act as a transcription factor that turns on genes that will increase oxygen delivery. We sequenced both of these genes and measured their mRNA levels at the beginning and end of each larval instar. Finally, we obtained an antibody to HIF-α and measured protein expression during the same time. Both mRNA and protein levels of HIFs were increased at the end of most instars. These data support the hypothesis that some insects may experience hypoxia at the end of an instar, which could be a signal for molting. SUMMARY STATEMENT As caterpillars grow within an instar, major tracheae do not increase in size, while metabolic demand increases. At the same life stages, caterpillars increased expression of hypoxia inducible factors, suggesting that they become hypoxic near the end of an instar.
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Affiliation(s)
- Taylor A Lundquist
- Department of Biological Sciences, North Dakota State University, Fargo, ND 58108-6050, United States
| | - Jeffrey D Kittilson
- Department of Biological Sciences, North Dakota State University, Fargo, ND 58108-6050, United States
| | - Rubina Ahsan
- Department of Biological Sciences, North Dakota State University, Fargo, ND 58108-6050, United States
| | - Kendra J Greenlee
- Department of Biological Sciences, North Dakota State University, Fargo, ND 58108-6050, United States.
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Kivelä SM, Viinamäki S, Keret N, Gotthard K, Hohtola E, Välimäki P. Elucidating mechanisms for insect body size: partial support for the oxygen-dependent induction of moulting hypothesis. ACTA ACUST UNITED AC 2018; 221:jeb.166157. [PMID: 29150451 DOI: 10.1242/jeb.166157] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2017] [Accepted: 11/14/2017] [Indexed: 11/20/2022]
Abstract
Body size is a key life history trait, and knowledge of its mechanistic basis is crucial in life history biology. Such knowledge is accumulating for holometabolous insects, whose growth is characterised and body size affected by moulting. According to the oxygen-dependent induction of moulting (ODIM) hypothesis, moult is induced at a critical mass at which oxygen demand of growing tissues overrides the supply from the tracheal respiratory system, which principally grows only at moults. Support for the ODIM hypothesis is controversial, partly because of a lack of proper data to explicitly test the hypothesis. The ODIM hypothesis predicts that the critical mass is positively correlated with oxygen partial pressure (PO2 ) and negatively with temperature. To resolve the controversy that surrounds the ODIM hypothesis, we rigorously test these predictions by exposing penultimate-instar Orthosia gothica (Lepidoptera: Noctuidae) larvae to temperature and moderate PO2 manipulations in a factorial experiment. The relative mass increment in the focal instar increased along with increasing PO2 , as predicted, but there was only weak suggestive evidence of the temperature effect. Probably owing to a high measurement error in the trait, the effect of PO2 on the critical mass was sex specific; high PO2 had a positive effect only in females, whereas low PO2 had a negative effect only in males. Critical mass was independent of temperature. Support for the ODIM hypothesis is partial because of only suggestive evidence of a temperature effect on moulting, but the role of oxygen in moult induction seems unambiguous. The ODIM mechanism thus seems worth considering in body size analyses.
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Affiliation(s)
- Sami M Kivelä
- Department of Zoology, Institute of Ecology and Earth Sciences, University of Tartu, Vanemuise 46, EE-51014 Tartu, Estonia
| | - Sonja Viinamäki
- Department of Ecology and Genetics, University of Oulu, PO Box 3000, 90014 University of Oulu, Oulu, Finland
| | - Netta Keret
- Department of Ecology and Genetics, University of Oulu, PO Box 3000, 90014 University of Oulu, Oulu, Finland
| | - Karl Gotthard
- Department of Zoology, Stockholm University, SE-10691 Stockholm, Sweden
| | - Esa Hohtola
- Department of Ecology and Genetics, University of Oulu, PO Box 3000, 90014 University of Oulu, Oulu, Finland
| | - Panu Välimäki
- Department of Ecology and Genetics, University of Oulu, PO Box 3000, 90014 University of Oulu, Oulu, Finland
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Harrison JF, Greenlee KJ, Verberk WCEP. Functional Hypoxia in Insects: Definition, Assessment, and Consequences for Physiology, Ecology, and Evolution. ANNUAL REVIEW OF ENTOMOLOGY 2018; 63:303-325. [PMID: 28992421 DOI: 10.1146/annurev-ento-020117-043145] [Citation(s) in RCA: 66] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Insects can experience functional hypoxia, a situation in which O2 supply is inadequate to meet oxygen demand. Assessing when functional hypoxia occurs is complex, because responses are graded, age and tissue dependent, and compensatory. Here, we compare information gained from metabolomics and transcriptional approaches and by manipulation of the partial pressure of oxygen. Functional hypoxia produces graded damage, including damaged macromolecules and inflammation. Insects respond by compensatory physiological and morphological changes in the tracheal system, metabolic reorganization, and suppression of activity, feeding, and growth. There is evidence for functional hypoxia in eggs, near the end of juvenile instars, and during molting. Functional hypoxia is more likely in species with lower O2 availability or transport capacities and when O2 need is great. Functional hypoxia occurs normally during insect development and is a factor in mediating life-history trade-offs.
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Affiliation(s)
- Jon F Harrison
- School of Life Sciences, Arizona State University, Tempe, Arizona 85287-4501;
| | - Kendra J Greenlee
- Department of Biological Sciences, North Dakota State University, Fargo, North Dakota 58108-6050;
| | - Wilco C E P Verberk
- Department of Animal Ecology and Ecophysiology, Radboud University, Nijmegen, Netherlands;
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10
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Adaptive developmental plasticity in a butterfly: mechanisms for size and time at pupation differ between diapause and direct development. Biol J Linn Soc Lond 2017. [DOI: 10.1093/biolinnean/blx047] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
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Luo GH, Yao J, Yang Q, Zhang ZC, Hoffmann AA, Fang JC. Variability in development of the striped rice borer, Chilo suppressalis (Lepidoptera: Pyralidae), due to instar number and last instar duration. Sci Rep 2016; 6:35231. [PMID: 27731388 PMCID: PMC5059691 DOI: 10.1038/srep35231] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2015] [Accepted: 09/22/2016] [Indexed: 11/27/2022] Open
Abstract
The striped stem borer, Chilo suppressalis (Walker), is an important insect pest of rice which shows substantial variation in developmental duration among individuals. This variation is currently poorly characterized but it is important from a control perspective because pesticides can only target early sensitive instars. It is unclear whether there are key stages that determine the length of developmental duration of individuals and/or whether variation in instar number contributes to this variation. In this study, a laboratory population and a population recently established from the field were used to test variation in development time across instar stages. The duration of developmental time of C. suppressalis started to diverge from the 5th instar onward. Individuals pupated at the 5th, 6th, 7th or even 8th instar stage. In both populations, both the instar at which the larva pupated and the duration of the last larval instar stage determined total developmental time of an individual. There was little impact of the developmental time of early instars on total developmental duration or on instar number prior to pupation. Sex influenced the number of instars but not development time within this number. The biological and applied significance of uneven development in C. suppressalis are discussed.
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Affiliation(s)
- Guang-Hua Luo
- Institute of Plant Protection, Jiangsu Academy of Agricultural Sciences, Nanjing 210014, China
| | - Jing Yao
- Institute of Plant Protection, Jiangsu Academy of Agricultural Sciences, Nanjing 210014, China
| | - Qiong Yang
- Institute of Plant Protection, Jiangsu Academy of Agricultural Sciences, Nanjing 210014, China
| | - Zhi-Chun Zhang
- Institute of Plant Protection, Jiangsu Academy of Agricultural Sciences, Nanjing 210014, China
| | - Ary A Hoffmann
- School of BioSciences, Bio 21 Institute, University of Melbourne, Parkville, Vic 3010, Australia
| | - Ji-Chao Fang
- Institute of Plant Protection, Jiangsu Academy of Agricultural Sciences, Nanjing 210014, China
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Kivelä SM, Lehmann P, Gotthard K. Do respiratory limitations affect metabolism of insect larvae before moulting: an empirical test at the individual level. J Exp Biol 2016; 219:3061-3071. [DOI: 10.1242/jeb.140442] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2016] [Accepted: 07/19/2016] [Indexed: 11/20/2022]
Abstract
Recent data suggest that oxygen limitation may induce moulting in larval insects. This oxygen dependent induction of moulting (ODIM) hypothesis stems from the fact that the tracheal respiratory system of insects grows primarily at moults, whereas tissue mass increases massively between moults. This may result in a mismatch between oxygen supply and demand at the end of each larval instar because oxygen demand of growing tissues exceeds the relatively fixed supply capacity of the respiratory system. The ODIM hypothesis predicts that, within larval instars, respiration and metabolic rates of an individual larva first increase with increasing body mass but eventually level off once the supply capacity of the tracheal system starts to constrain metabolism. Here, we provide the first individual-level test of this key prediction of the ODIM hypothesis. We use a novel methodology where we repeatedly measure respiration and metabolic rates throughout the penultimate- and final-instar larvae in the butterfly Pieris napi. In the penultimate instar, respiration and metabolic rates gradually decelerated along with growth, supporting the ODIM hypothesis. However, respiration and metabolic rates increased linearly during growth in the final instar, contradicting the prediction. Moreover, our data suggest considerable variation among individuals in the association between respiration rate and mass in the final instar. Overall, the results provide partial support for the ODIM hypothesis and suggest that oxygen limitation may emerge gradually within a larval instar. The results also suggest that there may be different moult induction mechanisms in larva-to-larva moults compared to the final metamorphic moult.
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Affiliation(s)
- Sami M. Kivelä
- Department of Zoology, Stockholm University, SE-10691 Stockholm, Sweden
- Present address: Department of Ecology, University of Oulu, PO Box 3000, 90014 University of Oulu, Finland
| | - Philipp Lehmann
- Department of Zoology, Stockholm University, SE-10691 Stockholm, Sweden
| | - Karl Gotthard
- Department of Zoology, Stockholm University, SE-10691 Stockholm, Sweden
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