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González-Gómez JC, Simone Y, Pérez LMF, Valenzuela-Rojas JC, van der Meijden A. Rapid prey manipulation and bite location preferences in three species of wandering spiders. Behav Processes 2024; 221:105083. [PMID: 39094759 DOI: 10.1016/j.beproc.2024.105083] [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: 04/01/2024] [Revised: 07/14/2024] [Accepted: 07/30/2024] [Indexed: 08/04/2024]
Abstract
Predator-prey interactions are the interspecific relationships of greatest interest in ecology. Spiders are among the most diverse and ubiquitous terrestrial predators on the planet. Their large dietary breadth is often linked with the development of specific predatory behaviors and morphological adaptations. However, studies on the predatory behavior of spiders have mostly focused on specialist species, leaving behind the ethological variability occurring in generalist species that allow them to respond to the different prey types. For three species of generalist wandering spiders, we searched images of predation events on the Internet to determine the most common prey. Subsequently, the focal predator species were then used in behavioral experiments. Using high-speed videos, handling patterns for different prey types (spider and cricket) were analyzed. Our results show a notable difference in handling patterns between prey types. We found that the spider prey was often rotated around the axis allowing the predator to bite in the ventral region of the prey and thus avoid a counterattack. Contrary, crickets were arbitrarily rotated. Our work may be an indication that these three species of generalist spiders have a preference for manipulating prey differently with a preference to rotate spiders, allowing them to exploit prey with various defensive mechanisms.
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Affiliation(s)
- Julio César González-Gómez
- Grupo de Investigación Biología y Ecología de Artrópodos (BEA), Corporación Huiltur, Neiva, Huila, Colombia; Programa de Doctorado en Ciencias Biológicas, Universidad del Tolima, Altos de Santa Helena, Ibagué, Colombia; Semillero de Investigación INVUSCO, Grupo GIPB, Licenciatura en Ciencias Naturales y Educación Ambiental, Universidad Surcolombiana, Neiva, Huila, Colombia.
| | - Yuri Simone
- Grupo de Investigación Biología y Ecología de Artrópodos (BEA), Corporación Huiltur, Neiva, Huila, Colombia; BIOPOLIS, CIBIO/InBio, Rua Padre Armando Quintas 7, Vairão 4485-661, Portugal.
| | - Lida Marcela Franco Pérez
- Facultad de Ciencias Naturales y Matemáticas, Universidad de Ibagué, Carrera 22, Calle 67, Ibagué, Colombia.
| | - Juan Carlos Valenzuela-Rojas
- Grupo de Investigación Biología y Ecología de Artrópodos (BEA), Corporación Huiltur, Neiva, Huila, Colombia; Semillero de Investigación INVUSCO, Grupo GIPB, Licenciatura en Ciencias Naturales y Educación Ambiental, Universidad Surcolombiana, Neiva, Huila, Colombia; Institución Educativa San Roque, Oporapa, Huila, Colombia.
| | - Arie van der Meijden
- Grupo de Investigación Biología y Ecología de Artrópodos (BEA), Corporación Huiltur, Neiva, Huila, Colombia; BIOPOLIS, CIBIO/InBio, Rua Padre Armando Quintas 7, Vairão 4485-661, Portugal.
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Lins AH, Lira AF, DeSouza AM. Variations in defensive behaviors according to diel period and sex in a litter-dwelling harvestman Pseudopucrolia discrepans (Opiliones: Gonyleptidae). Biologia (Bratisl) 2023. [DOI: 10.1007/s11756-023-01321-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
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3
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Antipredator responses of the morphs of an amphibian species match their differential predation pressures. Behav Ecol Sociobiol 2022. [DOI: 10.1007/s00265-022-03140-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
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4
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García LF, Valenzuela-Rojas JC, González-Gómez JC, Lacava M, van der Meijden A. Pinching or stinging? Comparing prey capture among scorpions with contrasting morphologies. J Venom Anim Toxins Incl Trop Dis 2022; 28:e20210037. [PMID: 35432495 PMCID: PMC8985449 DOI: 10.1590/1678-9199-jvatitd-2021-0037] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Accepted: 08/20/2021] [Indexed: 11/25/2022] Open
Abstract
Background: Scorpions can use their pincers and/or stingers to subdue and immobilize their prey. A scorpion can thus choose between strategies involving force or venom, or both, depending on what is required to subdue its prey. Scorpions vary greatly in the size and strength of their pincers, and in the efficacy of their venom. Whether this variability is driven by their defensive or prey incapacitation functionis unknown. In this study, we test if scorpion species with different pincer morphologies and venom efficacies use these weapons differently during prey subjugation. To that end, we observed Opisthacanthus elatus and Chactas sp. with large pincers and Centruroides edwardsii and Tityus sp. with slender pincers. Methods: The scorpion pinch force was measured, and behavioral experiments were performed with hard and soft prey (Blaptica dubia and Acheta domesticus). Stinger use, sting frequency and immobilization time were measured. Results: We found that scorpions with large pincers such as O. elatus produce more force and use the stinger less, mostly subjugating prey by crushing them with the pincers. In C. edwardsii and Tityus sp. we found they use their slender and relatively weak pincers for holding the prey, but seem to predominantly use the stinger to subjugate them. On the other hand, Chactas sp. uses both strategies although it has a high pinch force. Conclusions: Our results show that scorpionspecies with massive pincers and high pinch force as O. elatus use the stinger less for prey subjugation than scorpionspecies with slenderpincers.
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Soltan‐Alinejad P, Parsaei S, Dianat A, Nikbakhtazadeh M, Azizi K. Morphometric study and sexual dimorphism analyses in an Iranian population of Scorpio maurus (Arachnida: Scorpionidae). Ecol Evol 2021; 11:15630-15638. [PMID: 34824779 PMCID: PMC8601932 DOI: 10.1002/ece3.8211] [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: 12/15/2020] [Revised: 05/16/2021] [Accepted: 06/23/2021] [Indexed: 11/29/2022] Open
Abstract
Natural selection and sexual selection are cardinal factors in shaping the body of animals such as scorpions. Scorpio maurus (Scorpiones: Scorpionidae) has a worldwide distribution. Sexual dimorphism has been reported from this species in a study in Egypt. Morphometry is used to determine the sexual dimorphism between the two sexes. In the current study, scorpions were collected from six locations of the southern and northern provinces of Fars, Iran. In this study, 53 morphological characters of 15 specimens of each sex of Scorpio maurus were studied based on statistical analyses; however, dimorphism was only observed in 21 morphological characters, including chelicerae and carapace length, pedipalp characters, width of the second segment of metasoma, telson and pectin length, number of left pectin teeth, and some of the leg's segments. It means that these characters are in the control of sexual and natural selection. This study was performed for the first time on Scorpio maurus species in Iran.
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Affiliation(s)
- Parisa Soltan‐Alinejad
- Department of Medical Entomology and Vector ControlSchool of HealthShiraz University of Medical SciencesShirazIran
| | - Saman Parsaei
- Department of Medical Entomology and Vector ControlSchool of HealthShiraz University of Medical SciencesShirazIran
| | - Ali Dianat
- Department of Medical Entomology and Vector ControlSchool of HealthShiraz University of Medical SciencesShirazIran
| | - Mahmood Nikbakhtazadeh
- Department of Health Sciences and Human EcologyCalifornia State UniversitySan BernardinoCaliforniaUSA
| | - Kourosh Azizi
- Department of Medical Entomology and Vector ControlResearch Center for Health SciencesInstitute of HealthSchool of HealthShiraz University of Medical SciencesShirazIran
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6
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Simone Y, van der Meijden A. Armed stem to stinger: a review of the ecological roles of scorpion weapons. J Venom Anim Toxins Incl Trop Dis 2021; 27:e20210002. [PMID: 34527038 PMCID: PMC8425188 DOI: 10.1590/1678-9199-jvatitd-2021-0002] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2021] [Accepted: 03/18/2021] [Indexed: 12/24/2022] Open
Abstract
Scorpions possess two systems of weapons: the pincers (chelae) and the stinger (telson). These are placed on anatomically and developmentally well separated parts of the body, that is, the oral appendages and at the end of the body axis. The otherwise conserved body plan of scorpions varies most in the shape and relative dimensions of these two weapon systems, both across species and in some cases between the sexes. We review the literature on the ecological function of these two weapon systems in each of three contexts of usage: (i) predation, (ii) defense and (iii) sexual contests. In the latter context, we will also discuss their usage in mating. We first provide a comparative background for each of these contexts of usage by giving examples of other weapon systems from across the animal kingdom. Then, we discuss the pertinent aspects of the anatomy of the weapon systems, particularly those aspects relevant to their functioning in their ecological roles. The literature on the functioning and ecological role of both the chelae and the telson is discussed in detail, again organized by context of usage. Particular emphasis is given on the differences in morphology or usage between species or higher taxonomic groups, or between genders, as such cases are most insightful to understand the roles of each of the two distinct weapon systems of the scorpions and their evolutionary interactions. We aimed to synthesize the literature while minimizing conjecture, but also to point out gaps in the literature and potential future research opportunities.
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Affiliation(s)
- Yuri Simone
- CIBIO Research Centre in Biodiversity and Genetic Resources, InBIO, Porto, Portugal
| | - Arie van der Meijden
- CIBIO Research Centre in Biodiversity and Genetic Resources, InBIO, Porto, Portugal
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7
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Telheiro A, Coelho P, van der Meijden A. The effect of change in mass distribution due to defensive posture on gait in fat-tailed scorpions. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2021; 207:117-125. [PMID: 33751181 DOI: 10.1007/s00359-021-01467-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2020] [Revised: 02/11/2021] [Accepted: 02/15/2021] [Indexed: 10/22/2022]
Abstract
In terrestrial legged locomotion, the distribution of mass can influence the gait characteristics. This can be due to a change in the magnitude or distribution of the load. The latter occurs in scorpions when they lift their large metasoma from a trailing position in ambulatory posture to the well-known arched forward position in the defensive posture. We measured how locomotion changes between these two postures by recording scorpions walking using high-speed video. We found that the metasoma in the fat-tailed scorpion (Androctonus australis) represents about a quarter of the total mass. Moving this mass anteriorly over the body changes the position of the center of mass forward 8.15 ± 1.86 mm. We found this increases the overall duty factor, and particularly that of the second leg pair, even when taking the reduced speed in defensive posture into account. In the five scorpions we recorded, also the ipsilateral phase of leg pairs 3 and 4 differed in defensive posture. We found that the trajectory the 4th foot describes during a single stride also differed significantly between postures, showing this to be a sensitive measure of changes in gait. The change from an ambulatory to a defensive posture places different demands on the gait of scorpions, possibly largely due to the forward displacement of the center of mass.
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Affiliation(s)
- Ana Telheiro
- CIBIO-InBIO, Universidade do Porto, Campus Agrário de Vairão, Rua Padre Armando Quintas 7, Vila do Conde, 4485-661, Vairão, Portugal
| | - Pedro Coelho
- CIBIO-InBIO, Universidade do Porto, Campus Agrário de Vairão, Rua Padre Armando Quintas 7, Vila do Conde, 4485-661, Vairão, Portugal
| | - Arie van der Meijden
- CIBIO-InBIO, Universidade do Porto, Campus Agrário de Vairão, Rua Padre Armando Quintas 7, Vila do Conde, 4485-661, Vairão, Portugal.
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8
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Chuard PJC, Grant JWA, Ramnarine IW, Brown GE. Exploring the threat-sensitive predator avoidance hypothesis on mate competition in two wild populations of Trinidadian guppies. Behav Processes 2020; 180:104225. [PMID: 32860863 DOI: 10.1016/j.beproc.2020.104225] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2018] [Revised: 08/18/2020] [Accepted: 08/18/2020] [Indexed: 11/28/2022]
Abstract
The intensity of mate competition is often influenced by predation pressure. The threat-sensitive predator avoidance hypothesis predicts that prey should precisely adjust their fitness-related activities to the level of perceived acute predation risk and this effect should be stronger under high background risk. Individuals should compensate during periods of moderate risk for lost opportunities during high risk. Our study examined the interaction between acute and background predation risk on mate competition. Under laboratory conditions, we explored the effects of acute risk (low vs. high) using chemical alarm cue (AC; control (results presented in Chuard et al. (2016)) The effects of adult sex ratio on mating competition in male and female guppies (Poecilia reticulata) in two wild populations. Behav Process 129:1-10), 25 % concentration, and 100 % concentration), and population of origin (low vs. high background risk) on mate competition in guppies (Poecilia reticulata). Surprisingly, males favored courtship over forced mating under acute predation risk irrespective of background risk, potentially benefiting from a female preference for bold males. We discuss our results in the context of chemical threat-sensitivity and resource differences in defendability (e.g. mates vs. food).
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Affiliation(s)
- Pierre J C Chuard
- Department of Biology, Concordia University, Montréal, QC, H4B 1R6, Canada.
| | - James W A Grant
- Department of Biology, Concordia University, Montréal, QC, H4B 1R6, Canada.
| | - Indar W Ramnarine
- Departmentof Life Sciences, The University of the West Indies, St Augustine, Trinidad and Tobago.
| | - Grant E Brown
- Department of Biology, Concordia University, Montréal, QC, H4B 1R6, Canada.
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9
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Visser JH, Geerts S. Describing sexual dimorphism and fine scale spatial distributions in the Drab Thick-tail Scorpion, Parabuthus planicauda. AFRICAN ZOOLOGY 2020. [DOI: 10.1080/15627020.2020.1796525] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Affiliation(s)
- Jacobus H Visser
- Department of Conservation and Marine Sciences, Cape Peninsula University of Technology, Cape Town, South Africa
| | - Sjirk Geerts
- Department of Conservation and Marine Sciences, Cape Peninsula University of Technology, Cape Town, South Africa
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10
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Nelsen DR, David EM, Harty CN, Hector JB, Corbit AG. Risk Assessment and the Effects of Refuge Availability on the Defensive Behaviors of the Southern Unstriped Scorpion ( Vaejovis carolinianus). Toxins (Basel) 2020; 12:toxins12090534. [PMID: 32825487 PMCID: PMC7551882 DOI: 10.3390/toxins12090534] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2020] [Revised: 08/17/2020] [Accepted: 08/18/2020] [Indexed: 11/30/2022] Open
Abstract
Selection should favor individuals that acquire, process, and act on relevant environmental signals to avoid predation. Studies have found that scorpions control their use of venom: both when it is released and the total volume expelled. However, this research has not included how a scorpion’s awareness of environmental features influences these decisions. The current study tested 18 Vaejovis carolinianus scorpions (nine females and nine males) by placing them in circular arenas supplied with varying numbers (zero, two, or four) of square refuges and by tracking their movements overnight. The following morning, defensive behaviors were elicited by prodding scorpions on the chelae, prosoma, and metasoma once per second over 90 s. We recorded stings, venom use, chelae pinches, and flee duration. We found strong evidence that, across all behaviors measured, V. carolinianus perceived prods to the prosoma as more threatening than prods to the other locations. We found that stinging was a common behavior and became more dominant as the threat persisted. Though tenuous, we found evidence that scorpions’ defensive behaviors changed based on the number of refuges and that these differences may be sex specific. Our findings suggest that V. carolinianus can assess risk and features of the local environment and, therefore, alter their defensive strategies accordingly.
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González-Gómez JC, Valenzuela-Rojas JC, García LF, Franco Pérez LM, Guevara G, Buitrago S, Cubillos A, Van Der Meijden A. Sexual dimorphism in the biomechanical and toxicological performance in prey incapacitation of two morphologically distinct scorpion species (Chactas sp. and Centruroides sp.). Biol J Linn Soc Lond 2019. [DOI: 10.1093/biolinnean/blz146] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Abstract
Morphological differences between the sexes are a common feature in many groups of animals and can have important ecological implications for courtship, mating, access to prey and, in some cases, intersex niche partitioning. In this study, we evaluated the role of sexual dimorphism in the performance of the two structures that mediate the ability to access prey, the pinchers or chelae and the venomous stinger, in two species of scorpions with contrasting morphologies: Chactas sp., which has marked sexual dimorphism in the chelae, and Centruroides sp., which does not have such marked dimorphism in the chelae. We evaluated aspects such as chela pinch force, toxicity to prey (LD50) and the volume of venom in males and females of each species. We found significant differences between males and females of Chactas sp. in the chela pinch force, volume of venom and LD50. In contrast, for Centruroides sp., no differences between males and females were found in any of these traits. We discuss several potential selective regimes that could account for the pattern observed.
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Affiliation(s)
- Julio César González-Gómez
- Grupo de investigación Biología y Ecología de Artrópodos (BEA), Corporación Huiltur, Neiva, Huila y Departamento de Biología, Facultad de Ciencias, Universidad del Tolima, Altos de Santa Helena, Ibagué, Tolima, Colombia
| | - Juan Carlos Valenzuela-Rojas
- Grupo de investigación Biología y Ecología de Artrópodos (BEA), Corporación Huiltur, Neiva, Huila y Departamento de Biología, Facultad de Ciencias, Universidad del Tolima, Altos de Santa Helena, Ibagué, Tolima, Colombia
| | - Luis Fernando García
- Grupo de investigación Biología y Ecología de Artrópodos (BEA), Corporación Huiltur, Neiva, Huila y Departamento de Biología, Facultad de Ciencias, Universidad del Tolima, Altos de Santa Helena, Ibagué, Tolima, Colombia
- Grupo Multidisciplinario en Ecología para la Agricultura, Centro Universitario Regional del Este, Universidad de la República, Simón del Pino, 1132 Treinta y Tres, Uruguay
| | - Lida Marcela Franco Pérez
- Facultad de Ciencias Naturales y Matemáticas, Universidad de Ibagué, Carrera 22 Calle 67, Ibagué, Colombia
| | - Giovany Guevara
- Grupo de Investigación en Zoología (GIZ), Departamento de Biología, Facultad de Ciencias, Universidad del Tolima, Altos de Santa Helena, Ibagué, Tolima, Colombia
| | - Sandra Buitrago
- Grupo de investigación Biología y Ecología de Artrópodos (BEA), Corporación Huiltur, Neiva, Huila y Departamento de Biología, Facultad de Ciencias, Universidad del Tolima, Altos de Santa Helena, Ibagué, Tolima, Colombia
| | - Allison Cubillos
- Grupo de investigación Biología y Ecología de Artrópodos (BEA), Corporación Huiltur, Neiva, Huila y Departamento de Biología, Facultad de Ciencias, Universidad del Tolima, Altos de Santa Helena, Ibagué, Tolima, Colombia
| | - Arie Van Der Meijden
- Grupo de investigación Biología y Ecología de Artrópodos (BEA), Corporación Huiltur, Neiva, Huila y Departamento de Biología, Facultad de Ciencias, Universidad del Tolima, Altos de Santa Helena, Ibagué, Tolima, Colombia
- CIBIO-InBIO, Universidade do Porto, Campus Agrário de Vairão, Rua Padre Armando Quintas 7, 4485-661 Vairão, Vila do Conde, Portugal
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12
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Nystrom GS, Ward MJ, Ellsworth SA, Rokyta DR. Sex-based venom variation in the eastern bark centipede (Hemiscolopendra marginata). Toxicon 2019; 169:45-58. [DOI: 10.1016/j.toxicon.2019.08.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2019] [Revised: 07/25/2019] [Accepted: 08/08/2019] [Indexed: 11/15/2022]
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13
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Lira AFA, Almeida FMF, Albuquerque CMR. Reaction under the risk of predation: effects of age and sexual plasticity on defensive behavior in scorpion Tityus pusillus (Scorpiones: Buthidae). J ETHOL 2019. [DOI: 10.1007/s10164-019-00615-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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14
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Evans ERJ, Northfield TD, Daly NL, Wilson DT. Venom Costs and Optimization in Scorpions. Front Ecol Evol 2019. [DOI: 10.3389/fevo.2019.00196] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
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Rico-Guevara A, Hurme KJ. Intrasexually selected weapons. Biol Rev Camb Philos Soc 2019; 94:60-101. [PMID: 29924496 DOI: 10.1111/brv.12436] [Citation(s) in RCA: 78] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2017] [Revised: 05/14/2018] [Accepted: 05/18/2018] [Indexed: 01/24/2023]
Abstract
We propose a practical concept that distinguishes the particular kind of weaponry that has evolved to be used in combat between individuals of the same species and sex, which we term intrasexually selected weapons (ISWs). We present a treatise of ISWs in nature, aiming to understand their distinction and evolution from other secondary sex traits, including from 'sexually selected weapons', and from sexually dimorphic and monomorphic weaponry. We focus on the subset of secondary sex traits that are the result of same-sex combat, defined here as ISWs, provide not previously reported evolutionary patterns, and offer hypotheses to answer questions such as: why have only some species evolved weapons to fight for the opposite sex or breeding resources? We examined traits that seem to have evolved as ISWs in the entire animal phylogeny, restricting the classification of ISW to traits that are only present or enlarged in adults of one of the sexes, and are used as weapons during intrasexual fights. Because of the absence of behavioural data and, in many cases, lack of sexually discriminated series from juveniles to adults, we exclude the fossil record from this review. We merge morphological, ontogenetic, and behavioural information, and for the first time thoroughly review the tree of life to identify separate evolution of ISWs. We found that ISWs are only found in bilateral animals, appearing independently in nematodes, various groups of arthropods, and vertebrates. Our review sets a reference point to explore other taxa that we identify with potential ISWs for which behavioural or morphological studies are warranted. We establish that most ISWs come in pairs, are located in or near the head, are endo- or exoskeletal modifications, are overdeveloped structures compared with those found in females, are modified feeding structures and/or locomotor appendages, are most common in terrestrial taxa, are frequently used to guard females, territories, or both, and are also used in signalling displays to deter rivals and/or attract females. We also found that most taxa lack ISWs, that females of only a few species possess better-developed weapons than males, that the cases of independent evolution of ISWs are not evenly distributed across the phylogeny, and that animals possessing the most developed ISWs have non-hunting habits (e.g. herbivores) or are faunivores that prey on very small prey relative to their body size (e.g. insectivores). Bringing together perspectives from studies on a variety of taxa, we conceptualize that there are five ways in which a sexually dimorphic trait, apart from the primary sex traits, can be fixed: sexual selection, fecundity selection, parental role division, differential niche occupation between the sexes, and interference competition. We discuss these trends and the factors involved in the evolution of intrasexually selected weaponry in nature.
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Affiliation(s)
- Alejandro Rico-Guevara
- Department of Integrative Biology, University of California, Berkeley, 3040 Valley Life Sciences Building, Berkeley, CA, 94720, U.S.A.,Department of Ecology and Evolutionary Biology, University of Connecticut, 75 N. Eagleville Rd, Unit 3043, Storrs, CT, 06269, U.S.A.,Instituto de Ciencias Naturales, Universidad Nacional de Colombia, Código Postal 11001, Bogotá DC, Colombia
| | - Kristiina J Hurme
- Department of Integrative Biology, University of California, Berkeley, 3040 Valley Life Sciences Building, Berkeley, CA, 94720, U.S.A.,Department of Ecology and Evolutionary Biology, University of Connecticut, 75 N. Eagleville Rd, Unit 3043, Storrs, CT, 06269, U.S.A
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16
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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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Ward MJ, Ellsworth SA, Hogan MP, Nystrom GS, Martinez P, Budhdeo A, Zelaya R, Perez A, Powell B, He H, Rokyta DR. Female-biased population divergence in the venom of the Hentz striped scorpion (Centruroides hentzi). Toxicon 2018; 152:137-149. [PMID: 30096334 DOI: 10.1016/j.toxicon.2018.07.026] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2018] [Revised: 06/27/2018] [Accepted: 07/31/2018] [Indexed: 11/16/2022]
Abstract
Sex-biased genes are expressed at higher levels in one sex and contribute to phenotypic differences between males and females, as well as overall phenotypic variation within and among populations. Venom has evolved primarily for predation and defense, making venom expression a highly variable phenotype as a result of local adaptation. Several scorpion species have shown both intraspecific and intersexual venom variation, and males have been observed using venom in courtship and mating, suggesting the existence of venom-specific, sex-biased genes that may contribute to population divergence. We used reversed-phase high-performance liquid chromatography (RP-HPLC), Agilent protein bioanalyzer chips, nano-liquid chromatography mass spectrometry (nLC/MS/MS), and median lethal dose (LD50) assays in fruit flies (Drosophila melanogaster) and banded crickets (Gryllodes sigillatus) to investigate proteomic and functional venom variation within and among three Florida populations of the Hentz striped scorpion (Centruroides hentzi). We found significant venom variation among populations, with females, not males, being responsible for this divergence. We also found significant variation in venom expression within populations, with males contributing more to within population variation than females. Our results provide evidence that male and female scorpions experience different natural and sexual selective pressures that have led to the expression of sex-biased venom genes and that these genes may be consequential in population divergence.
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Affiliation(s)
- Micaiah J Ward
- Department of Biological Science, Florida State University, Tallahassee, FL, 32306, USA
| | - Schyler A Ellsworth
- Department of Biological Science, Florida State University, Tallahassee, FL, 32306, USA
| | - Michael P Hogan
- Department of Biological Science, Florida State University, Tallahassee, FL, 32306, USA
| | - Gunnar S Nystrom
- Department of Biological Science, Florida State University, Tallahassee, FL, 32306, USA
| | - Paul Martinez
- Department of Biological Science, Florida State University, Tallahassee, FL, 32306, USA
| | - Amisha Budhdeo
- Department of Biological Science, Florida State University, Tallahassee, FL, 32306, USA
| | - Roxana Zelaya
- Department of Biological Science, Florida State University, Tallahassee, FL, 32306, USA
| | - Alexander Perez
- Department of Biological Science, Florida State University, Tallahassee, FL, 32306, USA
| | - Barclay Powell
- Department of Biological Science, Florida State University, Tallahassee, FL, 32306, USA
| | - Huan He
- Institute of Molecular Biophysics and College of Medicine, Florida State University, Tallahassee, FL, 32306, USA
| | - Darin R Rokyta
- Department of Biological Science, Florida State University, Tallahassee, FL, 32306, USA.
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Simone Y, van Der Meijden A. Fast and fine versus strong and stout: a trade-off between chela closing force and speed across nine scorpion species. Biol J Linn Soc Lond 2017. [DOI: 10.1093/biolinnean/blx139] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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19
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Coelho P, Kaliontzopoulou A, Rasko M, Meijden A. A ‘striking’ relationship: scorpion defensive behaviour and its relation to morphology and performance. Funct Ecol 2017. [DOI: 10.1111/1365-2435.12855] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Pedro Coelho
- CIBIO Research Centre in Biodiversity and Genetic Resources InBIO Universidade do Porto Campus Agrário de Vairão, Rua Padre Armando Quintas, No. 7 4485‐661 Vairão, Vila do Conde Portugal
| | - Antigoni Kaliontzopoulou
- CIBIO Research Centre in Biodiversity and Genetic Resources InBIO Universidade do Porto Campus Agrário de Vairão, Rua Padre Armando Quintas, No. 7 4485‐661 Vairão, Vila do Conde Portugal
| | - Mykola Rasko
- CIBIO Research Centre in Biodiversity and Genetic Resources InBIO Universidade do Porto Campus Agrário de Vairão, Rua Padre Armando Quintas, No. 7 4485‐661 Vairão, Vila do Conde Portugal
| | - Arie Meijden
- CIBIO Research Centre in Biodiversity and Genetic Resources InBIO Universidade do Porto Campus Agrário de Vairão, Rua Padre Armando Quintas, No. 7 4485‐661 Vairão, Vila do Conde Portugal
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20
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van der Meijden A, Kleinteich T. A biomechanical view on stinger diversity in scorpions. J Anat 2017; 230:497-509. [PMID: 28028798 PMCID: PMC5345679 DOI: 10.1111/joa.12582] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/17/2016] [Indexed: 01/02/2023] Open
Abstract
Scorpions have elongated metasomas that bear a telson, which is used as a stinger for venom injection. There is a remarkable diversity in the use of the stinger among scorpions, comprising defensive behavior, prey subjugation and mating. This diversity could be reflected by the shape of the telson, as different stinging behaviors will result in very different functional demands. Here we explored the diversity of telson shapes in scorpions by providing morphological measurements, such as curvature and tip angle, as well as by testing stingers under load using finite element analysis (FEA). FEA models were loaded with forces scaled to the surface area of the models, to allow comparison of the relative strain energy based on shape alone. Load force angle was rotated to identify the optimal stinging angle based on the lowest strain energy. Aculeus length and mean aculeus height correlated with minimal strain energy. Optimal stinging angle correlated with tip angle, and differed from the tip angle by about 28.4 ± 6.22 °. We found that species that are more venomous have long aculei (stinger barbs) with a larger radius of curvature. FEA models of these longer aculei showed basal stress concentrations, indicating a potential greater risk of basal breakage due to shape alone. Telsons with shorter and thicker aculeus shapes showed stress concentrations at the tip only. Despite these marked differences in shape, we found no difference in the scaled strain energy between groups of species that are more venomous and less venomous groups of species. These results show that scorpion stingers may be biomechanically optimized, and this may indicate different usage of the stinger in different species.
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Affiliation(s)
- Arie van der Meijden
- CIBIO Research Centre in Biodiversity and Genetic ResourcesInBIOUniversidade do PortoVila do CondePortugal
| | - Thomas Kleinteich
- Department of ZoologyFunctional Morphology and BiomechanicsKielGermany
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21
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Chantall-Rocha S, Japyassú HF. Diffuse resistance courtship in the scorpion Rhopalurus rochai (Scorpiones: Buthidae). Behav Processes 2016; 135:45-55. [PMID: 27908665 DOI: 10.1016/j.beproc.2016.11.017] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2016] [Revised: 11/14/2016] [Accepted: 11/27/2016] [Indexed: 10/20/2022]
Abstract
Male-female courtship signals are frequently subject to arms races, with patterns of behaviour evolving reciprocally to manipulate the reproductive output. Female resistance should be particularly effective when asymmetrical offspring care occurs under low and unpredictable resource distribution, because this would increase maternal costs. Our hypothesis is that under these conditions females will evolve diffuse mating strategies to avoid predictable exploitation by male optimal counter tactics. Mating in scorpions is a complex process, and female resistance occurs through specific behaviours. Here we focus on the scorpion Rhopalurus rochai that inhabits strongly unpredictable arid habitats. We find that courtship success does not rely on typical resistance and stimulatory patterns of behaviours. The screening for prospective partners occurs in the pre-dance phase. Network statistics reveal that unsuccessful courtships are characterised by reduced complexity of interactions, a result typical of non-additive interactions that introduce unpredictability in the network. Unpredictable female resistance reduces male control over female reproduction more effectively than resistance through specific behavioural tactics; it could be selected in cases of extreme parental investment asymmetry, particularly in the context of resource fluctuation, as in the scorpion R. rochai, that inhabits environments with characteristic climatic unpredictability. Female resistance through a diffuse process would function as an extremely efficient screening device. The establishment of diffuse female resistance courtship would preclude the evolution of simple/single male optimal behavioural patterns, and thus the male-female arms races would reach a more complex state, whereby varied and contextually dependent male strategies would be required to settle the reproductive game.
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Affiliation(s)
- Shayanne Chantall-Rocha
- Núcleo de Etologia e Evolução, Instituto de Biologia, Universidade Federal da Bahia (UFBA), Rua Barão de Jeremoabo s/n - Ondina, 41170-290 Salvador, BA, Brazil
| | - Hilton F Japyassú
- Núcleo de Etologia e Evolução, Instituto de Biologia, Universidade Federal da Bahia (UFBA), Rua Barão de Jeremoabo s/n - Ondina, 41170-290 Salvador, BA, Brazil.
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22
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Miller DW, Jones AD, Goldston JS, Rowe MP, Rowe AH. Sex Differences in Defensive Behavior and Venom of The Striped Bark Scorpion Centruroides vittatus (Scorpiones: Buthidae). Integr Comp Biol 2016; 56:1022-1031. [PMID: 27471227 DOI: 10.1093/icb/icw098] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Studies of venom variability have advanced from describing the mechanisms of action and relative potency of medically important toxins to understanding the ecological and evolutionary causes of the variability itself. While most studies have focused on differences in venoms among taxa, populations, or age-classes, there may be intersexual effects as well. Striped bark scorpions (Centruroides vittatus) provide a good model for examining sex differences in venom composition and efficacy, as this species exhibits dramatic sexual dimorphism in both size and defensive behavior; when threatened by an enemy, larger, slower females stand and fight while smaller, fleeter males prefer to run. We here add evidence suggesting that male and female C. vittatus indeed have different defensive propensities; when threatened via an electrical stimulus, females were more likely to sting than were males. We reasoned that intersexual differences in defensive phenotypes would select for venoms with different functions in the two sexes; female venoms should be effective at predator deterrence, whereas male venoms, less utilized defensively, might be better suited to capturing prey or courting females. This rationale led to our predictions that females would inject more venom and/or possess more painful venom than males. We were wrong. While females do inject more venom than males in a defensive sting, females are also larger; when adjusted for body size, male and female C. vittatus commit equal masses of venom in a sting to a potential enemy. Additionally, house mice (Mus musculus) find an injection of male venom more irritating than an equal amount of female venom, likely because male venom contains more of the toxins that induce pain. Taken together, our results suggest that identifying the ultimate causes of venom variability will, as we move beyond adaptive storytelling, be hard-won.
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Affiliation(s)
- D W Miller
- *Neuroscience Program, Michigan State University, East Lansing, MI 48824, USA
| | - A D Jones
- Department of Biochemistry and Molecular Biology, Department of Chemistry, Michigan State University, East Lansing, MI 48824, USA
| | - J S Goldston
- *Neuroscience Program, Michigan State University, East Lansing, MI 48824, USA
| | - M P Rowe
- Department of Integrative Biology, Michigan State University, East Lansing, MI 48824, USA
| | - A H Rowe
- Neuroscience Program and Department of Integrative Biology, Michigan State University, East Lansing, MI 48824, USA
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23
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Variability in venom volume, flow rate and duration in defensive stings of five scorpion species. Toxicon 2015; 100:60-6. [DOI: 10.1016/j.toxicon.2015.04.011] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2014] [Revised: 04/21/2015] [Accepted: 04/22/2015] [Indexed: 11/18/2022]
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Fox GA, Cooper AM, Hayes WK. The dilemma of choosing a reference character for measuring sexual size dimorphism, sexual body component dimorphism, and character scaling: cryptic dimorphism and allometry in the scorpion Hadrurus arizonensis. PLoS One 2015; 10:e0120392. [PMID: 25793523 PMCID: PMC4368692 DOI: 10.1371/journal.pone.0120392] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2014] [Accepted: 01/22/2015] [Indexed: 11/19/2022] Open
Abstract
Sexual differences in morphology, ranging from subtle to extravagant, occur commonly in many animal species. These differences can encompass overall body size (sexual size dimorphism, SSD) or the size and/or shape of specific body parts (sexual body component dimorphism, SBCD). Interacting forces of natural and sexual selection shape much of the expression of dimorphism we see, though non-adaptive processes may be involved. Differential scaling of individual features can result when selection favors either exaggerated (positive allometry) or reduced (negative allometry) size during growth. Studies of sexual dimorphism and character scaling rely on multivariate models that ideally use an unbiased reference character as an overall measure of body size. We explored several candidate reference characters in a cryptically dimorphic taxon, Hadrurus arizonensis. In this scorpion, essentially every body component among the 16 we examined could be interpreted as dimorphic, but identification of SSD and SBCD depended on which character was used as the reference (prosoma length, prosoma area, total length, principal component 1, or metasoma segment 1 width). Of these characters, discriminant function analysis suggested that metasoma segment 1 width was the most appropriate. The pattern of dimorphism in H. arizonensis mirrored that seen in other more obviously dimorphic scorpions, with static allometry trending towards isometry in most characters. Our findings are consistent with the conclusions of others that fecundity selection likely favors a larger prosoma in female scorpions, whereas sexual selection may favor other body parts being larger in males, especially the metasoma, pectines, and possibly the chela. For this scorpion and probably most other organisms, the choice of reference character profoundly affects interpretations of SSD, SBCD, and allometry. Thus, researchers need to broaden their consideration of an appropriate reference and exercise caution in interpreting findings. We highly recommend use of discriminant function analysis to identify the least-biased reference character.
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Affiliation(s)
- Gerad A. Fox
- Department of Earth and Biological Sciences, School of Medicine, Loma Linda University, Loma Linda, California, United States of America
| | - Allen M. Cooper
- Department of Earth and Biological Sciences, School of Medicine, Loma Linda University, Loma Linda, California, United States of America
| | - William K. Hayes
- Department of Earth and Biological Sciences, School of Medicine, Loma Linda University, Loma Linda, California, United States of America
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