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Machado G, Burns M. Reproductive biology of harvestmen (Arachnida: Opiliones): a review of a rapidly evolving research field. Curr Zool 2024; 70:115-135. [PMID: 38476141 PMCID: PMC10926269 DOI: 10.1093/cz/zoac102] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2022] [Accepted: 12/18/2022] [Indexed: 03/14/2024] Open
Abstract
Harvestmen are a major arachnid order that has experienced a dramatic increase in biological knowledge in the 21st century. The publication of the book Harvestmen: The Biology of Opiliones in 2007 stimulated the development of many behavioral studies. Although the book is relatively recent, our understanding of the reproductive biology of harvestmen is already outdated due to the fast accumulation of new data. Our goal is to provide an updated review of the subject to serve as a benchmark for the following years. In the pre-copulatory phase, we explore the evolution of facultative parthenogenesis, the factors that may affect the types of mating system, and the role of nuptial gifts in courtship. Regarding the copulatory phase, harvestmen are unique arachnids because they have aflagellate spermatozoa and a penis with complex morphology. We discuss the implications of these two features for sperm competition and cryptic female choice. In the post-copulatory phase, we connect oviposition site selection and climate conditions to the widespread occurrence of resource defense polygyny, alternative reproductive tactics, and sexual dimorphism in several clades of tropical harvestmen. Finally, we present the different forms of parental care in the order, and discuss the benefits and costs of this behavior, which can be performed either by females or males. Throughout the review, we indicate gaps in our knowledge and subjects that deserve further studies. Hopefully, the information synthesized here will stimulate researchers worldwide to embrace harvestmen as a study system and to improve our effort to unravel the mysteries of their reproductive biology.
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Affiliation(s)
- Glauco Machado
- LAGE do Departamento de Ecologia, Instituto de Biociências, Universidade de São Paulo, São Paulo, Brazil
| | - Mercedes Burns
- Department of Biological Sciences, University of Maryland, Baltimore County, Baltimore, MD, USA
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Keith SA, Drury JP, McGill BJ, Grether GF. Macrobehaviour: behavioural variation across space, time, and taxa. Trends Ecol Evol 2023; 38:1177-1188. [PMID: 37661519 DOI: 10.1016/j.tree.2023.08.007] [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: 06/07/2023] [Revised: 08/02/2023] [Accepted: 08/10/2023] [Indexed: 09/05/2023]
Abstract
We explore how integrating behavioural ecology and macroecology can provide fundamental new insight into both fields, with particular relevance for understanding ecological responses to rapid environmental change. We outline the field of macrobehaviour, which aims to unite these disciplines explicitly, and highlight examples of research in this space. Macrobehaviour can be envisaged as a spectrum, where behavioural ecologists and macroecologists use new data and borrow tools and approaches from one another. At the heart of this spectrum, interdisciplinary research considers how selection in the context of large-scale factors can lead to systematic patterns in behavioural variation across space, time, and taxa, and in turn, influence macroecological patterns and processes. Macrobehaviour has the potential to enhance forecasts of future biodiversity change.
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Affiliation(s)
- Sally A Keith
- Lancaster Environment Centre, Lancaster University, Lancaster, LA1 4YQ, UK.
| | - Jonathan P Drury
- Department of Biosciences, Durham University, Durham, DH1 3LE, UK
| | - Brian J McGill
- School of Biology and Ecology and Mitchell Center for Sustainability Solutions, University of Maine, Orono, ME 04469, USA
| | - Gregory F Grether
- Department of Ecology and Evolutionary Biology, University of California Los Angeles, Los Angeles, CA 90095, USA
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3
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Bacon R, Washington D, Johnson MK, Burns M. The Geography of Sexual Conflict: A Synthetic Review. Am Nat 2023; 201:429-441. [PMID: 36848514 DOI: 10.1086/722797] [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] [Indexed: 11/03/2022]
Abstract
AbstractSexual conflict is a mechanism of selection driven by the divergent fitness interests between females and males. This disagreement can be great enough to promote antagonistic/defensive traits and behaviors. Although the existence of sexual conflict has been identified in many species, less research has explored the conditions that initially promote sexual conflict in animal mating systems. In previous work in Opiliones, we observed that morphological traits associated with sexual conflict occurred only in species from northern localities. We hypothesized that by shortening and compartmentalizing time periods optimal for reproduction, seasonality represents a geographic condition sufficient to promote sexual conflict. We conducted a systematic review of the literature on reproductive traits and behaviors. Using standardized criteria, we reviewed publications to identify whether subjects occurred in a temperate (high-seasonality) or tropical (low-seasonality) biome. After identifying and adjusting for a publication bias toward temperate research, we identified no significant difference in the strength of sexual conflict between temperate and tropical study systems. A comparison between the distribution of taxa studied in sexual conflict articles and articles focused on general biodiversity indicates that species with conflict-based mating systems more accurately represent the distribution of terrestrial animal species. These findings contribute to ongoing efforts to characterize the origins of sexual conflict as well as life history traits that covary with sexual conflict.
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Toyama KS, Mahler DL, Goodman RM. Climate shapes patterns of sexual size and shape dimorphism across the native range of the green anole lizard, Anolis carolinensis (Squamata: Dactyloidae). Biol J Linn Soc Lond 2022. [DOI: 10.1093/biolinnean/blac136] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Abstract
Geographical variation in sexual size dimorphism (SSD) can result from the combined effects of environmental and sexual selection. To understand the determinants of SSD across geographical landscapes, we tested for relationships between SSD and climatic variables in the widespread lizard Anolis carolinensis. To distinguish alternative hypotheses for observed patterns of variation in SSD, we also examined sex-specific patterns of body size evolution and asked whether SSD was associated with certain patterns of sexual shape dimorphism. We found strong evidence for Rensch’s rule (an increase in male-biased SSD with average body size) in A. carolinensis and evidence for the reversed version of Bergmann’s rule (an increase in body size towards warmer environments) in males. Across populations, SSD was positively related to temperature; however, female body size was not related to any climatic variable, suggesting that the latitudinal gradient of SSD might be driven by a gradient in the intensity of sexual selection acting on males. Sexual size dimorphism was positively correlated with sexual dimorphism in head shape and negatively correlated with limb length dimorphism, suggesting that sexual selection in males might drive the evolution of SSD and that differences in size and limb shape between sexes might represent alternative strategies to avoid competition for the same resources.
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Affiliation(s)
- Ken S Toyama
- Department of Ecology and Evolutionary Biology, University of Toronto , ON , Canada M5S 3B2
| | - D Luke Mahler
- Department of Ecology and Evolutionary Biology, University of Toronto , ON , Canada M5S 3B2
| | - Rachel M Goodman
- Biology Department, Hampden-Sydney College , Hampden-Sydney, VA , USA
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5
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Reproductive phenology of the spider Micrommata ligurina (C.L. Koch, 1845) (Araneae; Sparassidae) across an elevational gradient in Northeast Algeria. EKOLÓGIA (BRATISLAVA) 2022. [DOI: 10.2478/eko-2022-0026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Abstract
Decreased ambient temperature and shorter reproductive seasons are the two main obstacles that ectotherms face at higher elevations. Studies have shown that some life history traits such as phenological windows of activity, duration, and fitness components vary as elevation increases. However, studies on the elevational gradient at the southern range limit of species are lacking. In this study, we aim at assessing some aspects of the life history of a spider species, the sprassid Micrommata ligurina (C.L. Koch, 1845), across an elevational gradient from 30 to 1030 m in Northeast Algeria. There was strong evidence of an elevational shift in the phenology of reproduction with a delay rate of 2.2 days per 100 m of elevation, and the three quantiles of the phenology (10, 50, and 90%) shifted with the same magnitude across elevation. In all sites from low to high elevation, the species showed a decrease in number of individuals. The mean number of eggs was 200 ± 35 eggs, and the mean number of hatching eggs was 110.9 ± 23.5 eggs. The clutch size at high elevation sites was higher than that of low-elevation sites, but in contrast, the hatching success was higher at lower elevation sites. Overall, the species exhibited clear elevational clines in life history traits and abundance, suggesting a high potential of plasticity. This work constitutes the first study carried out on spider species ecology in the region.
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Chelini MC, Brock K, Yeager J, Edwards DL. Environmental drivers of sexual dimorphism in a lizard with alternative mating strategies. J Evol Biol 2021; 34:1241-1255. [PMID: 34101919 DOI: 10.1111/jeb.13881] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2020] [Revised: 03/29/2021] [Accepted: 05/12/2021] [Indexed: 11/28/2022]
Abstract
Understanding the relative importance of sexual and natural selection in shaping morphological traits is a long-standing goal of evolutionary ecology. Male-biased sexual size dimorphism (SSD) is typically associated with male-male competition. Similarly, male polymorphisms are considered a consequence of competitive social interactions. This classic paradigm overlooks the fact that environmental factors mediate social interactions and can lead to ecological adaptations. Common side-blotched lizards, Uta stansburiana, are a model system for this paradigm due to well-known rock-paper-scissors social dynamics between male morphs. SSD in this species has been considered primarily a consequence of social interactions, with male size resulting from the number of morphs in each population and female size being constrained through fecundity benefits. We test if the environment explains intraspecific variation in SSD and number of male morphs in U. stansburiana. By compiling data from 49 populations, we show that environmental variables are stronger predictors of SSD than the number of male morphs. Similarly, we show that the environment mediates SSD and potentially contributes to morph loss in colder environments. We propose that the environment favours smaller males in areas of high seasonality. Our results demonstrate the importance of the environment as a mediator of SSD.
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Affiliation(s)
| | - Kinsey Brock
- School of Natural Sciences, University of California, Merced, Merced, CA, USA
| | - Justin Yeager
- School of Natural Sciences, University of California, Merced, Merced, CA, USA
| | - Danielle L Edwards
- School of Natural Sciences, University of California, Merced, Merced, CA, USA
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7
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Leith NT, Macchiano A, Moore MP, Fowler-Finn KD. Temperature impacts all behavioral interactions during insect and arachnid reproduction. CURRENT OPINION IN INSECT SCIENCE 2021; 45:106-114. [PMID: 33831604 DOI: 10.1016/j.cois.2021.03.005] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/02/2020] [Revised: 03/17/2021] [Accepted: 03/23/2021] [Indexed: 05/26/2023]
Abstract
Temperature shapes the processes and outcomes of behaviors that occur throughout the progression of insect and arachnid mating interactions and reproduction. Here, we highlight how temperature impacts precopulatory activity levels, competition among rivals, communication with potential mates, and the relative costs and benefits of mating. We review how both the prevailing temperature conditions during reproductive activity and the temperatures experienced early in life influence mating-related behavior. To effectively predict the consequences of global warming for insect and arachnid mating behavior, we advocate for future work that universally integrates a function-valued approach to measuring thermal sensitivity. A function-valued approach will be especially useful for understanding how fine-scale temperature variation shapes current and future selection on mating interactions.
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Affiliation(s)
- Noah T Leith
- Department of Biology, Saint Louis University, United States.
| | | | - Michael P Moore
- Living Earth Collaborative, Washington University in St. Louis, United States
| | - Kasey D Fowler-Finn
- Department of Biology, Saint Louis University, United States; Living Earth Collaborative, Washington University in St. Louis, United States
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8
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Sumarto BKA, Nofrianto AB, Mokodongan DF, Lawelle SA, Masengi KWA, Fujimoto S, Yamahira K. Variation in Mating Behaviors Between a Tropical and a Temperate Species of Medaka Fishes. Zoolog Sci 2021; 38:45-50. [PMID: 33639717 DOI: 10.2108/zs200114] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2020] [Accepted: 08/27/2020] [Indexed: 11/17/2022]
Abstract
In medaka fishes, the family Adrianichthyidae, tropical species are known to be sexually more dimorphic than temperate species. If this reflects that tropical species are exposed to stronger sexual-selection pressures than temperate species, mating behaviors may also differ between tropical and temperate species. Our mating experiments revealed that males of Oryzias woworae, a tropical species of the family, perform "chasing" another male more frequently than males of O. sakaizumii, a temperate congener, and that male-male "combats" of O. woworae tended to be followed by chasing compared with combats of O. sakaizumii males, indicating that O. woworae males are more aggressive in male-male interactions than O. sakaizumii males. Males of O. woworae also performed "approaching" a female and "mating dance" more frequently than O. sakaizumii males, indicating that O. woworae males are also more active in courting females. Males of O. sakaizumii often omitted "mating dance" in their mating sequences, supporting this view. Moreover, O. woworae females tended to reject male "wrapping", an attempt for fertilization, more frequently than O. sakaizumii females, suggesting that O. woworae females are choosier in mating than O. sakaizumii females. These findings are concordant with the view that O. woworae is exposed to stronger sexual-selection pressures than O. sakaizumii.
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Affiliation(s)
- Bayu K A Sumarto
- Tropical Biosphere Research Center, University of the Ryukyus, Okinawa 903-0213, Japan
| | - Andy B Nofrianto
- Faculty of Fisheries and Marine Science, Halu Oleo University, Kendari 93232, Indonesia
| | - Daniel F Mokodongan
- Faculty of Fisheries and Marine Science, Halu Oleo University, Kendari 93232, Indonesia
| | - Sjamsu A Lawelle
- Faculty of Fisheries and Marine Science, Halu Oleo University, Kendari 93232, Indonesia
| | - Kawilarang W A Masengi
- Faculty of Fisheries and Marine Science, Sam Ratulangi University, Manado 95115, Indonesia
| | - Shingo Fujimoto
- Graduate School of Medicine, University of the Ryukyus, Okinawa 903-0125, Japan,
| | - Kazunori Yamahira
- Tropical Biosphere Research Center, University of the Ryukyus, Okinawa 903-0213, Japan,
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9
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Sumarto BKA, Kobayashi H, Kakioka R, Tanaka R, Maeda K, Tran HD, Koizumi N, Morioka S, Bounsong V, Watanabe K, Musikasinthorn P, Tun S, Yun LKC, Anoop VK, Raghavan R, Masengi KWA, Fujimoto S, Yamahira K. Latitudinal variation in sexual dimorphism in a freshwater fish group. Biol J Linn Soc Lond 2020. [DOI: 10.1093/biolinnean/blaa166] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Abstract
Tropical animals are characterized by showy ornaments and conspicuous body colours as compared with their temperate relatives. Some recent studies have hypothesized that sexual selection pressures are stronger in the tropics than in the temperate zone. Although negative correlations between latitude and the degree of sexual dimorphism would support this hypothesis, phylogeny should be taken into account in such comparative studies. Comparisons of the degree of sexual dimorphism in body size and fin lengths among species of the Adrianichthyidae, a freshwater fish family having a wide geographical range throughout Southeast and East Asia, revealed that lower latitude species are sexually more dimorphic in all characters than higher latitude species. Phylogenetic generalized least squares analyses using a mitochondrial DNA phylogeny demonstrated that the negative correlations between latitude and the degree of sexual dimorphism become non-significant when phylogeny is considered, but that the variance in the degree of sexual dimorphism is explained not only by phylogeny but also almost equally by latitude. Ancestral state reconstruction indicated that sexual dimorphisms have evolved independently even within major clades. These findings are consistent with the view that tropical species are exposed to stronger sexual selection pressures than temperate species. We discuss possible causes of the latitudinal variation in sexual selection pressure.
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Affiliation(s)
- Bayu K A Sumarto
- Tropical Biosphere Research Center, University of the Ryukyus, Okinawa, Japan
| | - Hirozumi Kobayashi
- Tropical Biosphere Research Center, University of the Ryukyus, Okinawa, Japan
| | - Ryo Kakioka
- Tropical Biosphere Research Center, University of the Ryukyus, Okinawa, Japan
| | - Rieko Tanaka
- World Medaka Aquarium, Nagoya Higashiyama Zoo and Botanical Gardens, Nagoya, Japan
| | - Ken Maeda
- Okinawa Institute of Science and Technology Graduate University, Okinawa, Japan
| | - Hau D Tran
- Faculty of Biology, Hanoi National University of Education, Hanoi, Vietnam
| | - Noriyuki Koizumi
- Institute for Rural Engineering, National Agriculture and Food Research Organization, Ibaraki, Japan
| | - Shinsuke Morioka
- Fisheries Division, Japan International Research Center for Agricultural Sciences, Ibaraki, Japan
| | | | | | | | - Sein Tun
- Inlay Lake Wildlife Sanctuary, Nature and Wildlife Conservation Division, Forest Department, Ministry of Natural Resources and Environmental Conservation, Myanmar
| | - L K C Yun
- Inlay Lake Wildlife Sanctuary, Nature and Wildlife Conservation Division, Forest Department, Ministry of Natural Resources and Environmental Conservation, Myanmar
| | - V K Anoop
- School of Ocean Science and Technology, Kerala University of Fisheries and Ocean Studies, Kochi, India
| | - Rajeev Raghavan
- Department of Fisheries Resource Management, Kerala University of Fisheries and Ocean Studies, Kochi, India
| | | | - Shingo Fujimoto
- Graduate School of Medicine, University of the Ryukyus, Okinawa, Japan
| | - Kazunori Yamahira
- Tropical Biosphere Research Center, University of the Ryukyus, Okinawa, Japan
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10
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García-Roa R, Garcia-Gonzalez F, Noble DWA, Carazo P. Temperature as a modulator of sexual selection. Biol Rev Camb Philos Soc 2020; 95:1607-1629. [PMID: 32691483 DOI: 10.1111/brv.12632] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2019] [Revised: 06/10/2020] [Accepted: 06/12/2020] [Indexed: 12/25/2022]
Abstract
A central question in ecology and evolution is to understand why sexual selection varies so much in strength across taxa; it has long been known that ecological factors are crucial to this. Temperature is a particularly salient abiotic ecological factor that modulates a wide range of physiological, morphological and behavioural traits, impacting individuals and populations at a global taxonomic scale. Furthermore, temperature exhibits substantial temporal variation (e.g. daily, seasonally and inter-seasonally), and hence for most species in the wild sexual selection will regularly unfold in a dynamic thermal environment. Unfortunately, studies have so far almost completely neglected the role of temperature as a modulator of sexual selection. Here, we outline the main pathways through which temperature can affect the intensity and form (i.e. mechanisms) of sexual selection, via: (i) direct effects on secondary sexual traits and preferences (i.e. trait variance, opportunity for selection and trait-fitness covariance), and (ii) indirect effects on key mating parameters, sex-specific reproductive costs/benefits, trade-offs, demography and correlated abiotic factors. Building upon this framework, we show that, by focusing exclusively on the first-order effects that environmental temperature has on traits linked with individual fitness and population viability, current global warming studies may be ignoring eco-evolutionary feedbacks mediated by sexual selection. Finally, we tested the general prediction that temperature modulates sexual selection by conducting a meta-analysis of available studies experimentally manipulating temperature and reporting effects on the variance of male/female reproductive success and/or traits under sexual selection. Our results show a clear association between temperature and sexual selection measures in both sexes. In short, we suggest that studying the feedback between temperature and sexual selection processes may be vital to developing a better understanding of variation in the strength of sexual selection in nature, and its consequences for population viability in response to environmental change (e.g. global warming).
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Affiliation(s)
- Roberto García-Roa
- Behaviour and Evolution, Ethology Lab, Cavanilles Institute of Biodiversity and Evolutionary Biology, University of Valencia, C/Catedrático José Beltrán 2, Paterna, Valencia, 46980, Spain
| | - Francisco Garcia-Gonzalez
- Doñana Biological Station, Spanish Research Council CSIC, c/Americo Vespucio, 26, Isla de la Cartuja, Sevilla, 41092, Spain.,Centre for Evolutionary Biology, School of Biological Sciences, The University of Western Australia, 35 Stirling Highway, Crawley, Western Australia, 6009, Australia
| | - Daniel W A Noble
- Ecology and Evolution Research Centre, School of Biological, Earth and Environmental Sciences, University of New South Wales, Sydney, New South Wales, 2052, Australia.,Division of Ecology and Evolution, Research School of Biology, The Australian National University, Canberra, Australian Capital Territory, 2061, Australia
| | - Pau Carazo
- Behaviour and Evolution, Ethology Lab, Cavanilles Institute of Biodiversity and Evolutionary Biology, University of Valencia, C/Catedrático José Beltrán 2, Paterna, Valencia, 46980, Spain
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11
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Iglesias PP, Pereyra MO. Population dynamics and reproductive phenology of a harvestman in a tidal freshwater wetland. AN ACAD BRAS CIENC 2020; 92:e20181123. [PMID: 32236299 DOI: 10.1590/0001-3765202020181123] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2018] [Accepted: 03/13/2019] [Indexed: 11/22/2022] Open
Abstract
There is a great amount of ecological information for terrestrial arthropods in several types of habitats, but few studies have focused on populations living in tidal freshwater wetlands. During a two-year field survey, we studied the temporal dynamics of the harvestman Discocyrtus prospicuus inhabiting a freshwater wetland exposed to predictable tides and unpredictable floods. We also explored the effects of temperature, precipitation, and tide level on the population dynamics and reproductive phenology. Our findings are markedly different from those reported in other harvestman species living in different habitats and also from conspecific populations living in the mainland. Adults, subadults, and juveniles remain active throughout the year, and a long breeding season was observed. However, the number of adults, subadults, juveniles, and egg clutches showed clear variations over the year without a consistent seasonal pattern. Contrary to the general pattern in harvestmen, no climatic variables were significant predictors of abundance fluctuations. We discuss the potential masking effect of unpredictable flood events, obscuring the relationship between abundance and abiotic factors. In addition, given that climatic conditions seem to favor harvestmen activity throughout the year, we also hypothesized that abundance variations could be driven mainly by biotic rather than by abiotic interactions.
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Affiliation(s)
- Patricia P Iglesias
- División Aracnología, Museo Argentino de Ciencias Naturales "Bernardino Rivadavia" - CONICET, Av. Ángel Gallardo, 470, C1405DJR Buenos Aires, Argentina
| | - Martín O Pereyra
- División Herpetología, Museo Argentino de Ciencias Naturales "Bernardino Rivadavia" - CONICET, Av. Ángel Gallardo, 470, C1405DJR Buenos Aires, Argentina
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12
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McLean CJ, Garwood RJ, Brassey CA. Sexual dimorphism in the Arachnid orders. PeerJ 2018; 6:e5751. [PMID: 30416880 PMCID: PMC6225839 DOI: 10.7717/peerj.5751] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2018] [Accepted: 09/14/2018] [Indexed: 01/21/2023] Open
Abstract
Sexual differences in size and shape are common across the animal kingdom. The study of sexual dimorphism (SD) can provide insight into the sexual- and natural-selection pressures experienced by males and females in different species. Arachnids are diverse, comprising over 100,000 species, and exhibit some of the more extreme forms of SD in the animal kingdom, with the males and females of some species differing dramatically in body shape and/or size. Despite this, research on arachnid SD has primarily focused on specific clades as opposed to observing traits across arachnid orders, the smallest of which have received comparatively little attention. This review provides an overview of the research to date on the trends and potential evolutionary drivers for SD and sexual size dimorphism (SSD) in individual arachnid orders, and across arachnids as a whole. The most common trends across Arachnida are female-biased SSD in total body size, male-biased SSD in relative leg length and SD in pedipalp length and shape. However, the evolution of sexually dimorphic traits within the group is difficult to elucidate due to uncertainty in arachnid phylogenetic relationships. Based on the dataset we have gathered here, we highlight gaps in our current understanding and suggest areas for future research.
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Affiliation(s)
- Callum J. McLean
- School of Science and the Environment, Manchester Metropolitan University, Manchester, UK
| | - Russell J. Garwood
- School of Earth and Environmental Sciences, University of Manchester, Manchester, UK
- Earth Sciences Department, Natural History Museum, London, UK
| | - Charlotte A. Brassey
- School of Science and the Environment, Manchester Metropolitan University, Manchester, UK
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13
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Solano-Brenes D, García-Hernández S, Machado G. All the better to bite you with! Striking intrasexual differences in cheliceral size define two male morphs in an Amazonian arachnid. Biol J Linn Soc Lond 2018. [DOI: 10.1093/biolinnean/bly120] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Affiliation(s)
- Diego Solano-Brenes
- Universidad de Costa Rica, Sede Rodrigo Facio, San Pedro de Montes de Oca, San José, Costa Rica
| | - Solimary García-Hernández
- Programa de Pós-graduação em Ecologia, Instituto de Biociências, Universidade de São Paulo, São Paulo, Brazil
| | - Glauco Machado
- LAGE do Departamento de Ecologia, Instituto de Biociências, Universidade de São Paulo, São Paulo, SP, Brazil
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14
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Colville JF, Picker MD, Cowling RM. Feeding ecology and sexual dimorphism in a speciose flower beetle clade (Hopliini: Scarabaeidae). PeerJ 2018; 6:e4632. [PMID: 29942673 PMCID: PMC6015485 DOI: 10.7717/peerj.4632] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2017] [Accepted: 03/23/2018] [Indexed: 01/18/2023] Open
Abstract
The relationship between feeding ecology and sexual dimorphism is examined in a speciose South African monkey beetle clade. We test whether feeding and mating at a fixed site (embedding guild) is associated with greater levels of sexual dimorphism and possibly sexual selection than species using unpredictable feeding resources (non-embedding guild). Sexual dimorphism was measured using a point scoring system for hind leg and colour across the two feeding guilds for >50% of the regional fauna. Quantification of hind leg dimorphism using a scoring system and allometric scaling were used to identify traits subject to sexual selection. Feeding guild had a significant effect on hind leg dimorphism, with embedders having high and non-embedders low scores. The sessile and defendable distribution of females on stable platform flowers may favour contests and associated hind leg weaponry. In contrast, degree of colour dimorphism between the sexes was not associated with any particular feeding guild, and may serve to reduce male conflict and combat. Embedder males had high proportions (∼76%) of species with positive allometric slopes for almost all hind leg traits. For male non-embedders, only ∼37% of species showed positive scaling relationships. Phylogenetic data, in conjunction with behavioural data on the function of leg weaponry and visual signalling among males is needed to better understand the link between sexual dimorphism and sexual selection in the radiation of the monkey beetles.
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Affiliation(s)
- Jonathan F. Colville
- Kirstenbosch Research Centre, South African National Biodiversity Institute, Cape Town, South Africa
- Statistics in Ecology, Environment and Conservation, University of Cape Town, Rondebosch, South Africa
- Department of Biological Sciences, University of Cape Town, Rondebosch, South Africa
| | - Mike D. Picker
- Department of Biological Sciences, University of Cape Town, Rondebosch, South Africa
| | - Richard M. Cowling
- African Centre for Coastal Palaeoscience, Nelson Mandela Metropolitan University, Port Elizabeth, South Africa
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15
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McArthur IW, de Miranda GS, Seiter M, Chapin KJ. Global patterns of sexual dimorphism in Amblypygi. ZOOL ANZ 2018. [DOI: 10.1016/j.jcz.2018.02.005] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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García‐Hernández S, Machado G. Effectiveness of maternal egg attendance in an exclusively cave‐dwelling harvestman (Arachnida: Opiliones). J Zool (1987) 2017. [DOI: 10.1111/jzo.12452] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Affiliation(s)
- S. García‐Hernández
- Programa de Pós‐graduação em Ecologia Instituto de Biociências Universidade de São Paulo São Paulo Brazil
| | - G. Machado
- LAGE do Departamento de Ecologia Instituto de Biociências Universidade de São Paulo São Paulo Brazil
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