Deceived, but not betrayed: static allometry suggests female ornaments in the long-tailed dance fly (Rhamphomyia longicauda) exaggerate condition to males

2022 ◽  
Author(s):  
Jessica H. Browne ◽  
Darryl T. Gwynne
Keyword(s):  
Female Ornaments ◽  
Dance Fly ◽  
Static Allometry

Static allometry suggests female ornaments in the long-tailed dance fly (Rhamphomyia longicauda) are not deceptive

2021 ◽  
Author(s):  
Jessica H Browne ◽  
Darryl T. Gwynne
Keyword(s):  
Body Size ◽  
Prey Capture ◽  
Hind Femur ◽  
Positive Allometry ◽  
Female Ornamentation ◽  
Female Ornaments ◽  
Ornamental Traits ◽  
Steep Slopes ◽  
Dance Fly ◽  
Static Allometry

Abstract Despite their prevalence in nature, the evolution of sex-specific female ornaments is still not well understood. Although in some cases (often carotenoid-based ornaments) they appear to honestly signal quality, such as fecundity, it has been suggested that some female ornaments have evolved to deceptively to obtain matings. We address these two hypotheses in the long-tailed dance fly ( Rhamphomyia longicauda ), where females possess two sex-specific ornaments: pinnate scales on the hind femur and tibia and abdominal sacs that are inflated in female-biased display swarms. Although several studies have suggested that female ornaments in this species are deceptive, evidence is mixed and requires further investigation. Here, we use static allometry (with body size as a proxy for condition) of both ornamental and non-ornamental traits in females (and homologous non-ornamental traits in males) in order to determine whether they are honest or deceptive signals of quality. Most male traits scaled isometrically with body size, however male leg hairs showed positive static allometry, probably because they are involved in nuptial-prey capture or in grasping mates. Ornamental traits in females (abdomen area and tibia scale length) showed significant positive allometry and had steep slopes relative to non-ornamental traits. As larger females invest more in ornamentation relative to smaller females, this suggests that these traits are likely honest, condition-dependent signals of quality. We note that honesty and deception are not mutually exclusive hypotheses. Individuals may vary in their signalling strategy, resulting in, for example, deception from some low condition individuals but honesty overall. Although our finding of positive allometry makes it unlikely this occurs in long tailed dance flies, simultaneous honesty and deception should be considered in future studies of female ornamentation.

scholarly journals Sexual selection on multiple female ornaments in dance flies

2018 ◽  
Vol 285 (1887) ◽  
pp. 20181525 ◽  
Author(s):  
Rosalind L. Murray ◽  
Jill Wheeler ◽  
Darryl T. Gwynne ◽  
Luc F. Bussière
Keyword(s):  
Sexual Conflict ◽  
Female Ornaments ◽  
Conflict Model ◽  
Probable Role ◽  
Ornament Evolution ◽  
Female Specific ◽  
Male Specific ◽  
Dance Fly ◽  
Trait Space

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.

scholarly journals Stabilizing sexual selection for female ornaments in a dance fly

2012 ◽  
Vol 25 (7) ◽  
pp. 1233-1242 ◽  
Author(s):  
J. WHEELER ◽  
D. T. GWYNNE ◽  
L. F. BUSSIÈRE
Keyword(s):  
Sexual Selection ◽  
Female Ornaments ◽  
Selection For ◽  
Dance Fly

Female ornaments hinder escape from spider webs in a role-reversed swarming dance fly

2007 ◽  
Vol 73 (6) ◽  
pp. 1077-1082 ◽  
Author(s):  
Darryl T. Gwynne ◽  
Luc F. Bussière ◽  
Tracie M. Ivy
Keyword(s):  
Spider Webs ◽  
Female Ornaments ◽  
Dance Fly

scholarly journals The role of functional constraints in nonrandom mating patterns for a dance fly with female ornaments

2019 ◽  
Vol 32 (9) ◽  
pp. 984-993 ◽  
Author(s):  
Rosalind L. Murray ◽  
Darryl T. Gwynne ◽  
Luc F. Bussière
Keyword(s):  
Functional Constraints ◽  
Nonrandom Mating ◽  
Mating Patterns ◽  
Female Ornaments ◽  
Dance Fly

A Cretaceous dance fly (Diptera: Empididae) from Botswana

1989 ◽  
Vol 14 (2) ◽  
pp. 233-241 ◽  
Author(s):  
SASKIA B. WATERS
Keyword(s):  
Dance Fly

Sexual dimorphism, ontogeny and static allometry of a semi-fossorial snake (genus Atractus)

2020 ◽  
Vol 287 ◽  
pp. 95-104
Author(s):  
Arthur Diesel Abegg ◽  
Paulo Passos ◽  
Conrado Mario-da-Rosa ◽  
Weverton dos Santos Azevedo ◽  
Leandro Malta-Borges ◽  
...  
Keyword(s):  
Sexual Dimorphism ◽  
Static Allometry
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