1
|
Murray RL, Gwynne DT, Bussière LF. Mating and Sexual Selection in Empidine Dance Flies (Empididae). INSECTS 2022; 13:839. [PMID: 36135540 PMCID: PMC9502509 DOI: 10.3390/insects13090839] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/10/2022] [Revised: 08/31/2022] [Accepted: 09/08/2022] [Indexed: 06/16/2023]
Abstract
Species whose behaviour or morphology diverges from typical patterns can provide unique insights on the evolutionary forces that promote diversity. Darwin recognised that while elaborate sexually selected traits mostly occurred among males, in a few species females possess such traits. Some species from the subfamily Empidinae (Diptera: Empididae) are among the animals that are often invoked to illustrate female ornaments. Empidines include taxa that exhibit varying levels of female ornament expression; some species possess multiple, elaborate female-specific ornaments while others have fewer and more modest adornments, and many species are altogether lacking discernible sexual ornamentation. This continuous variation in display traits in the Empidinae provides unique opportunities to explore the causes and consequences of sexually selected ornament expression. Here, we review the literature on sexual selection and mating systems in these flies and synthesise the evidence for various evolutionary forces that could conceivably create this impressive morphological and behavioural diversity, despite evolutionary constraints on female ornament exaggeration that help to explain its general rarity among animals. We also suggest some aspects of diversity that remain relatively unexplored or poorly understood, and close by offering suggestions for future research progress in the evolutionary ecology of mating behaviour among empidine flies.
Collapse
Affiliation(s)
- Rosalind L. Murray
- Biology Department, University of Toronto Mississauga, Mississauga, ON L5L 1C6, Canada
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, ON M5S 3B2, Canada
| | - Darryl T. Gwynne
- Biology Department, University of Toronto Mississauga, Mississauga, ON L5L 1C6, Canada
| | - Luc F. Bussière
- Department of Biological and Environmental Sciences & Gothenburg Global Biodiversity Centre, University of Gothenburg, 405 30 Göteborg, Sweden
| |
Collapse
|
2
|
Murray RL, Herridge EJ, Ness RW, Wiberg RAW, Bussière LF. Competition for access to mates predicts female-specific ornamentation and male investment in relative testis size. Evolution 2020; 74:1741-1754. [PMID: 32352568 DOI: 10.1111/evo.13986] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2019] [Revised: 03/26/2020] [Accepted: 04/05/2020] [Indexed: 11/30/2022]
Abstract
Sexually selected ornaments are highly variable and the factors that drive variation in ornament expression are not always clear. Rare instances of female-specific ornament evolution (such as in some dance fly species) are particularly puzzling. While some evidence suggests that such rare instances represent straightforward reversals of sexual selection intensity, the distinct nature of trade-offs between ornaments and offspring pose special constraints in females. To examine whether competition for access to mates generally favors heightened ornament expression, we built a phylogeny and conducted a comparative analysis of Empidinae dance fly taxa that display female-specific ornaments. We show that species with more female-biased operational sex ratios in lek-like mating swarms have greater female ornamentation, and in taxa with more ornate females, male relative testis investment is increased. These findings support the hypothesis that ornament diversity in dance flies depends on female receptivity to mates, which is associated with contests for nutritious nuptial gifts provided by males. Moreover, our results suggest that increases in female receptivity lead to higher levels of sperm competition among males. The incidence of both heightened premating sexual selection on females and postmating selection on males contradicts assertions that sex roles are straightforwardly reversed in dance flies.
Collapse
Affiliation(s)
- Rosalind L Murray
- Biology Department, University of Toronto, Mississauga, Ontario, L5L 1C6, Canada.,Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, Ontario, M5S 3B2, Canada.,Biological and Environmental Sciences, University of Stirling, Stirling, Scotland, FK9 4LA, United Kingdom
| | - Elizabeth J Herridge
- Biological and Environmental Sciences, University of Stirling, Stirling, Scotland, FK9 4LA, United Kingdom
| | - Rob W Ness
- Biology Department, University of Toronto, Mississauga, Ontario, L5L 1C6, Canada.,Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, Ontario, M5S 3B2, Canada
| | - R Axel W Wiberg
- Department of Environmental Sciences, Evolutionary Biology, University of Basel, Basel, 4051, Switzerland
| | - Luc F Bussière
- Biological and Environmental Sciences, University of Stirling, Stirling, Scotland, FK9 4LA, United Kingdom
| |
Collapse
|
3
|
Murray RL, Gwynne DT, Bussière LF. The role of functional constraints in nonrandom mating patterns for a dance fly with female ornaments. J Evol Biol 2019; 32:984-993. [DOI: 10.1111/jeb.13500] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2019] [Revised: 06/10/2019] [Accepted: 06/14/2019] [Indexed: 11/30/2022]
Affiliation(s)
- Rosalind L. Murray
- Department of Ecology and Evolutionary Biology University of Toronto Toronto Ontario Canada
- Biology Department University of Toronto at Mississauga Mississauga Ontario Canada
- Biological and Environmental Sciences University of Stirling Stirling UK
| | - Darryl T. Gwynne
- Biology Department University of Toronto at Mississauga Mississauga Ontario Canada
| | - Luc F. Bussière
- Biological and Environmental Sciences University of Stirling Stirling UK
| |
Collapse
|
4
|
Murray RL, Wheeler J, Gwynne DT, Bussière LF. Sexual selection on multiple female ornaments in dance flies. Proc Biol Sci 2018; 285:rspb.2018.1525. [PMID: 30232158 DOI: 10.1098/rspb.2018.1525] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2018] [Accepted: 08/28/2018] [Indexed: 11/12/2022] Open
Abstract
Sex-specific ornaments typically occur in males, but they can also develop in females. While there are several models concerning the evolution of male-specific ornaments, it is not clear how, or under what circumstances, those models apply to female-specific ornament evolution. Here, we present a manipulative field experiment that explores the theoretical 'trait space' of multiple female-specific ornaments to study how these unusual traits evolved. We measured the attractiveness of two female-specific ornaments (pinnate leg scales and inflatable abdominal sacs) in the dance fly Rhamphomyia longicauda in a wild mating swarm. We found significant directional preferences for larger ornaments of both types; however, variation in one of the ornaments (abdominal sacs) was almost three times more effective at improving attractiveness. The abdominal ornament was consistently effective in increasing attractiveness to males regardless of leg ornament expression, while leg ornament size was only effective if abdominal ornaments were very small. These results are consistent with predictions from a sexual conflict model of ornament expression in supporting the probable role of deception in the evolution of female-specific ornaments among dance flies. Sexual conflict can be an important force in generating elaborate sex-specific ornaments in females as well as males.
Collapse
Affiliation(s)
- Rosalind L Murray
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, Ontario, Canada M5S 3B2 .,Department of Biology, University of Toronto at Mississauga, Mississauga, Ontario, Canada L5L 1C6.,Biological and Environmental Sciences, University of Stirling, Stirling FK9 4LA, UK
| | - Jill Wheeler
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, Ontario, Canada M5S 3B2
| | - Darryl T Gwynne
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, Ontario, Canada M5S 3B2.,Department of Biology, University of Toronto at Mississauga, Mississauga, Ontario, Canada L5L 1C6
| | - Luc F Bussière
- Biological and Environmental Sciences, University of Stirling, Stirling FK9 4LA, UK
| |
Collapse
|