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Pal A, Joshi M, Thaker M. Too much information? Males convey parasite levels using more signal modalities than females utilise. J Exp Biol 2024; 227:jeb246217. [PMID: 38054353 PMCID: PMC10906484 DOI: 10.1242/jeb.246217] [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: 06/02/2023] [Accepted: 11/30/2023] [Indexed: 12/07/2023]
Abstract
Elaborate sexual signals are thought to have evolved and be maintained to serve as honest indicators of signaller quality. One measure of quality is health, which can be affected by parasite infection. Cnemaspis mysoriensis is a diurnal gecko that is often infested with ectoparasites in the wild, and males of this species express visual (coloured gular patches) and chemical (femoral gland secretions) traits that receivers could assess during social interactions. In this paper, we tested whether ectoparasites affect individual health, and whether signal quality is an indicator of ectoparasite levels. In wild lizards, we found that ectoparasite level was negatively correlated with body condition in both sexes. Moreover, some characteristics of both visual and chemical traits in males were strongly associated with ectoparasite levels. Specifically, males with higher ectoparasite levels had yellow gular patches with lower brightness and chroma, and chemical secretions with a lower proportion of aromatic compounds. We then determined whether ectoparasite levels in males influence female behaviour. Using sequential choice trials, wherein females were provided with either the visual or the chemical signals of wild-caught males that varied in ectoparasite level, we found that only chemical secretions evoked an elevated female response towards less parasitised males. Simultaneous choice trials in which females were exposed to the chemical secretions from males that varied in parasite level further confirmed a preference for males with lower parasites loads. Overall, we find that although health (body condition) or ectoparasite load can be honestly advertised through multiple modalities, the parasite-mediated female response is exclusively driven by chemical signals.
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Affiliation(s)
- Arka Pal
- Centre for Ecological Sciences, Indian Institute of Science, Bangalore 560 012, India
- Institute of Science and Technology Austria, 3400 Klosterneuburg, Austria
| | - Mihir Joshi
- Centre for Ecological Sciences, Indian Institute of Science, Bangalore 560 012, India
| | - Maria Thaker
- Centre for Ecological Sciences, Indian Institute of Science, Bangalore 560 012, India
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Murali G, Meiri S, Roll U. Chemical signaling glands are unlinked to species diversification in lizards. Evolution 2023; 77:1829-1841. [PMID: 37279331 DOI: 10.1093/evolut/qpad101] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2022] [Revised: 05/17/2023] [Accepted: 05/31/2023] [Indexed: 06/08/2023]
Abstract
Sexual selection has long been thought to increase species diversification. Sexually selected traits, such as sexual signals that contribute to reproductive isolation, were thought to promote diversification. However, studies exploring links between sexually selected traits and species diversification have thus far primarily focused on visual or acoustic signals. Many animals often employ chemical signals (i.e., pheromones) for sexual communications, but large-scale analyses on the role of chemical communications in driving species diversification have been missing. Here, for the first time, we investigate whether traits associated with chemical communications-the presence of follicular epidermal glands-promote diversification across 6,672 lizard species. In most analyses, we found no strong association between the presence of follicular epidermal glands and species diversification rates, either across all lizard species or at lower phylogenetic scales. Previous studies suggest that follicular gland secretions act as species recognition signals that prevent hybridization during speciation in lizards. However, we show that geographic range overlap was no different in sibling species pairs with and without follicular epidermal glands. Together, these results imply that either follicular epidermal glands do not primarily function in sexual communications or sexually selected traits in general (here chemical communication) have a limited effect on species diversification. In our additional analysis accounting for sex-specific differences in glands, we again found no detectable effect of follicular epidermal glands on species diversification rates. Thus, our study challenges the general role of sexually selected traits in broad-scale species diversification patterns.
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Affiliation(s)
- Gopal Murali
- Jacob Blaustein Center for Scientific Cooperation, The Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Midreshet Ben-Gurion, Israel
- Mitrani Department of Desert Ecology, The Swiss Institute for Dryland Environments and Energy Research, The Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Midreshet Ben-Gurion, Israel
- Department of Ecology and Evolutionary Biology, University of Arizona, Tucson, AZ, United States
| | - Shai Meiri
- School of Zoology and The Steinhardt Museum of Natural History, Tel Aviv University, Tel Aviv, Beersheva, Sede-Boqer Campus, 8499000, Israel
| | - Uri Roll
- Mitrani Department of Desert Ecology, The Swiss Institute for Dryland Environments and Energy Research, The Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Midreshet Ben-Gurion, Israel
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Zozaya SM, Teasdale LC, Tedeschi LG, Higgie M, Hoskin CJ, Moritz C. Initiation of speciation across multiple dimensions in a rock-restricted, tropical lizard. Mol Ecol 2023; 32:680-695. [PMID: 36394360 PMCID: PMC10099344 DOI: 10.1111/mec.16787] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2022] [Revised: 11/02/2022] [Accepted: 11/08/2022] [Indexed: 11/18/2022]
Abstract
Population isolation and concomitant genetic divergence, resulting in strong phylogeographical structure, is a core aspect of speciation initiation. If and how speciation then proceeds and ultimately completes depends on multiple factors that mediate reproductive isolation, including divergence in genomes, ecology and mating traits. Here we explored these multiple dimensions in two young (Plio-Pleistocene) species complexes of gekkonid lizards (Heteronotia) from the Kimberley-Victoria River regions of tropical Australia. Using mitochondrial DNA screening and exon capture phylogenomics, we show that the rock-restricted Heteronotia planiceps exhibits exceptional fine-scale phylogeographical structure compared to the codistributed habitat generalist Heteronotia binoei. This indicates pervasive population isolation and persistence in the rock-specialist, and thus a high rate of speciation initiation across this geographically complex region, with levels of genomic divergence spanning the "grey zone" of speciation. Proximal lineages of H. planiceps were often separated by different rock substrates, suggesting a potential role for ecological isolation; however, phylogenetic incongruence and historical introgression were inferred between one such pair. Ecomorphological divergence among lineages within both H. planiceps and H. binoei was limited, except that limestone-restricted lineages of H. planiceps tended to be larger than rock-generalists. By contrast, among-lineage divergence in the chemical composition of epidermal pore secretions (putative mating trait) exceeded ecomorphology in both complexes, but with less trait overlap among lineages in H. planiceps. This system-particularly the rock-specialist H. planiceps-highlights the role of multidimensional divergence during incipient speciation, with divergence in genomes, ecomorphology and chemical signals all at play at very fine spatial scales.
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Affiliation(s)
- Stephen M Zozaya
- Research School of Biology, Australian National University, Australian Capital Territory, Canberra, Australia
| | - Luisa C Teasdale
- Research School of Biology, Australian National University, Australian Capital Territory, Canberra, Australia.,Department of Molecular Biology, Max Planck Institute for Developmental Biology, Tübingen, Germany
| | - Leonardo G Tedeschi
- Research School of Biology, Australian National University, Australian Capital Territory, Canberra, Australia
| | - Megan Higgie
- College of Science and Engineering, James Cook University, Queensland, Townsville, Australia
| | - Conrad J Hoskin
- College of Science and Engineering, James Cook University, Queensland, Townsville, Australia
| | - Craig Moritz
- Research School of Biology, Australian National University, Australian Capital Territory, Canberra, Australia
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Agarwal I, Thackeray T, Khandekar A. A multitude of spots! Five new microendemic species of the Cnemaspis gracilis group (Squamata: Gekkonidae) from massifs in the Shevaroy landscape, Tamil Nadu, India. VERTEBRATE ZOOLOGY 2022. [DOI: 10.3897/vz.72.e94799] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
South Asian Cnemaspis are one of the most diverse clades of gekkonids in South Asia with their highest diversity in the Western Ghats and Sri Lanka. These geckos include only a few nocturnal species and are largely diurnal or cathemeral and restricted to relatively cool habitats. One of the prominently diurnal subgroups in South Asian Cnemaspis is the bangara clade, which includes six species distributed in southern India on the eastern slopes of the Western Ghats, the southern Eastern Ghats and Palghat Gap. In this paper, we describe five more species of the bangara clade from the Shevaroyan landscape, including three from Kollimalai and one each from Yercaud and Pachaimalai, all in Tamil Nadu. These new species show 4.6–19.7 % uncorrected sequence divergence on the mitochondrial ND2 gene from each other and known species of the bangara clade and are morphologically diagnosable in body size, the number of paravertebral tubercles between limb insertions, the number of dorsal tubercle rows, the number of ventral scale rows across the belly, the number of femoral and precloacal pores and poreless scales separating these series, and aspects of colouration. The discovery of these five new species adds to the growing discoveries of cool-adapted species in southern India outside the Western Ghats and highlights the role of sky-islands in diversification. The Shevaroyan landscape shows high levels of microendemism with eight species distributed in an area of < 2000 km2, and all these species restricted to much smaller areas of actual distribution. With an area of < 500 km2 respectively, the massif of Pachaimalai has a single endemic and the massifs of Yercaud and Kollimalai have three endemic Cnemaspis species each.
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Zozaya SM, Teasdale LC, Moritz C, Higgie M, Hoskin CJ. Composition of a chemical signalling trait varies with phylogeny and precipitation across an Australian lizard radiation. J Evol Biol 2022; 35:919-933. [PMID: 35665557 DOI: 10.1111/jeb.14031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2022] [Revised: 04/18/2022] [Accepted: 05/06/2022] [Indexed: 12/01/2022]
Abstract
The environment presents challenges to the transmission and detection of animal signalling systems, resulting in selective pressures that can drive signal divergence amongst populations in disparate environments. For chemical signals, climate is a potentially important selective force because factors such as temperature and moisture influence the persistence and detection of chemicals. We investigated an Australian lizard radiation (Heteronotia) to explore relationships between a sexually dimorphic chemical signalling trait (epidermal pore secretions) and two key climate variables: temperature and precipitation. We reconstructed the phylogeny of Heteronotia with exon capture phylogenomics, estimated phylogenetic signal in amongst-lineage chemical variation and assessed how chemical composition relates to temperature and precipitation using multivariate phylogenetic regressions. High estimates of phylogenetic signal indicate that the composition of epidermal pore secretions varies amongst lineages in a manner consistent with Brownian motion, although there are deviations to this, with stark divergences coinciding with two phylogenetic splits. Accounting for phylogenetic non-independence, we found that amongst-lineage chemical variation is associated with geographic variation in precipitation but not temperature. This contrasts somewhat with previous lizard studies, which have generally found an association between temperature and chemical composition. Our results suggest that geographic variation in precipitation can affect the evolution of chemical signalling traits, possibly influencing patterns of divergence amongst lineages and species.
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Affiliation(s)
- Stephen M Zozaya
- Research School of Biology, Australian National University, Acton, Australian Capital Territory, Australia.,College of Science and Engineering, James Cook University, Townsville, Queensland, Australia
| | - Luisa C Teasdale
- Research School of Biology, Australian National University, Acton, Australian Capital Territory, Australia.,Department of Molecular Biology, Max Planck Institute for Developmental Biology, Tübingen, Germany
| | - Craig Moritz
- Research School of Biology, Australian National University, Acton, Australian Capital Territory, Australia
| | - Megan Higgie
- College of Science and Engineering, James Cook University, Townsville, Queensland, Australia
| | - Conrad J Hoskin
- College of Science and Engineering, James Cook University, Townsville, Queensland, Australia
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Joshi M, Ellsworth B, Thaker M. Single components of complex chemical signals convey sex identity and individual variation. Anim Behav 2022. [DOI: 10.1016/j.anbehav.2022.02.013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022]
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Neves CN, Pillay N. Variation in brain volume in nine populations and three taxa of the African striped mouse Rhabdomys. J Morphol 2022; 283:618-636. [PMID: 35175641 DOI: 10.1002/jmor.21463] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2021] [Revised: 01/30/2022] [Accepted: 02/10/2022] [Indexed: 11/06/2022]
Abstract
Brain size can vary between populations in different environments because of different selection pressures on behaviours, such as learning and memory, related to spatial, social and environmental differences. We investigated the variation in total and broad-scale regional brain size in the murid rodent genus Rhabdomys from different environments. We assessed taxon-, population- and sex-level differences in total and regional brain volume in three populations each of three taxa (arid-occurring R. pumilio and mesic-occurring R. dilectus chakae and R. d. dilectus) originating across southern Africa. We μCT-scanned crania obtained from museums in South Africa and used digital software to create endocasts and extract total endocranium and regional volumes: olfactory bulb, anterior cerebrum, posterior cerebrum, cerebellum volume, and petrosal volume. Total endocranial volume scaled with basal skull length and all region volumes scaled with total endocranial volume. We found taxon-, and population-level differences in total endocranial volume. Relative anterior and posterior cerebrum volume did not differ significantly between taxa or populations, but relative cerebellum volume was larger in arid populations than mesic populations. Relative olfactory bulb volume was larger in mesic R. dilectus than in the R. pumilio, but petrosal lobule volume was larger in R. pumilio populations than in R. dilectus. Males had larger total endocranial volumes than females. Drivers of larger total endocranial volumes in R. pumilio are not immediately clear from our results. Environmental seasonality of food availability, cognitive buffering and locomotion may all correlate with total endocranial volume size, whereas the influence of sociality cannot be excluded. The environment and degree of semi-arboreality are likely driving variation in cerebellum, olfactory bulb and petrosal lobule volumes. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Candice Nikita Neves
- School of Animal, Plant, and Environmental Sciences, University of the Witwatersrand, 1 Jan Smuts Ave, Private Bag 3, Johannesburg, South Africa
| | - Neville Pillay
- School of Animal, Plant, and Environmental Sciences, University of the Witwatersrand, 1 Jan Smuts Ave, Private Bag 3, Johannesburg, South Africa
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Poma-Soto F, Narváez AE, Romero-Carvajal A. Visual Signaling in the Semi-Fossorial Lizard Pholidobolus montium (Gymnophthalmidae). Animals (Basel) 2021; 11:ani11113022. [PMID: 34827756 PMCID: PMC8614464 DOI: 10.3390/ani11113022] [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: 08/31/2021] [Revised: 09/19/2021] [Accepted: 09/20/2021] [Indexed: 11/16/2022] Open
Abstract
Simple Summary Lizards display multiple communication modalities, through chemical, visual, vocal, or tactile signals which mediate sociality, reproduction, territoriality, competition, and other complex interactions among individuals. In some species that dwell on the surface, it has been shown that multimodal communication is possible, for example, visual and chemical communication. It is less known if lizards that dwell in caves or burrows (fossorial) also use visual signals. By studying behavior in a semi-fossorial lizard from the northern Ecuadorian Andes, we have discovered that they can use visual signals like leg movements and body arching to communicate. In this manuscript, we describe these observations and discuss the potential roles of these signals. This is the first description of such behaviors in semi-fossorial lizards. Abstract It has been suggested that gymnophthalmids, like most semi-fossorial lacertoids, rely more in chemical cues to communicate, in comparison to other groups, like Iguanids, on which communication is mostly based on visual signaling. We present the first description of visual signaling in the Andean lizard Pholidobolusmontium (Gymnophthalmidae) and a complete ethogram based on ex situ observations (34 different types of behaviors including positions and simple movements). Through the design of conspecific stimulus experiments, we were able to recognize leg-waving as a visual signal, as it is only displayed in presence of conspecifics or in presence of a mirror and was one of first and most frequent displays in this context. We also detected other visual displays like neck-arching and tail-undulation which may also be relevant as visual signals. Based on our results, we propose that visual signaling is also possible in semi-fossorial lizards; however, further studies regarding chemical signal recognition and color detection are required to confirm our hypothesis.
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Affiliation(s)
- Franco Poma-Soto
- Escuela de Ciencias Biológicas, Pontificia Universidad Católica del Ecuador, Quito 170525, Ecuador
| | - Andrea E. Narváez
- Fundacion Great Leaf, De las Azucenas N47-60 y Av. Eloy Alfaro, Quito 170503, Ecuador
| | - Andrés Romero-Carvajal
- Escuela de Ciencias Biológicas, Pontificia Universidad Católica del Ecuador, Quito 170525, Ecuador
- Correspondence: ; Tel.: +593-22-991700 (ext. 1280)
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