Males evolve to be more harmful under increased sexual conflict intensity in a seed beetle

2020 ◽  
Vol 31 (2) ◽  
pp. 591-597 ◽  
Author(s):  
Kathryn B McNamara ◽  
Nadia S Sloan ◽  
Sian E Kershaw ◽  
Emile van Lieshout ◽  
Leigh W Simmons
Keyword(s):  
Sexual Conflict ◽  
Reproductive Tract ◽  
Callosobruchus Maculatus ◽  
Female Reproductive Tract ◽  
Female Resistance ◽  
Seed Beetle ◽  
Copulation Behavior ◽  
Tract Damage ◽  
Full Factorial ◽  
Conflict Intensity

Abstract One conspicuous manifestation of sexual conflict is traumatic mating, in which male genitalia damage the female during copulation. The penis of the seed beetle, Callosobruchus maculatus, is covered in spines that damage the female reproductive tract. Females kick males ostensibly to shorten these harmful copulations. How these iconic conflict behaviors coevolve in response to sexual conflict intensity can provide insight into the economics of these traits. We examined whether male harm and female resistance coevolved in response to elevated sexual conflict. We quantified copulation behavior and female reproductive tract damage of individuals from replicated populations evolving for 32 generations under low or high sexual conflict (female- and male-biased treatments, respectively). First, we permitted females ad libitum matings with males from either sex-ratio treatment, recording her tract damage and longevity. Second, we performed a full-factorial cross of matings by males and females from each of the replicate populations, recording mating and kicking duration and reproductive output. We found manipulation of sexual conflict intensity led to the evolution of male harmfulness, but not female resistance to harm. We also demonstrate that female kicking does not respond to sexual conflict intensity, suggesting it does not function to mitigate male harm in this species. Our findings demonstrate the complexities of behavioral and morphological coevolutionary responses to sexual conflict intensity in an important model species.

scholarly journals Sexual conflict and correlated evolution between male persistence and female resistance traits in the seed beetle Callosobruchus maculatus

2017 ◽  
Vol 284 (1855) ◽  
pp. 20170132 ◽  
Author(s):  
Liam R. Dougherty ◽  
Emile van Lieshout ◽  
Kathryn B. McNamara ◽  
Joe A. Moschilla ◽  
Göran Arnqvist ◽  
...  
Keyword(s):  
Sexual Conflict ◽  
Male Genitalia ◽  
Callosobruchus Maculatus ◽  
Negative Relationship ◽  
Female Reproductive Tract ◽  
Female Resistance ◽  
Correlated Evolution ◽  
Male And Female ◽  
Seed Beetle ◽  
Trade Offs

Traumatic mating (or copulatory wounding) is an extreme form of sexual conflict whereby male genitalia physically harm females during mating. In such species females are expected to evolve counter-adaptations to reduce male-induced harm. Importantly, female counter-adaptations may include both genital and non-genital traits. In this study, we examine evolutionary associations between harmful male genital morphology and female reproductive tract morphology and immune function across 13 populations of the seed beetle Callosobruchus maculatus . We detected positive correlated evolution between the injuriousness of male genitalia and putative female resistance adaptations across populations. Moreover, we found evidence for a negative relationship between female immunity and population productivity, which suggests that investment in female resistance may be costly due to the resource trade-offs that are predicted between immunity and reproduction. Finally, the degree of female tract scarring (harm to females) was greater in those populations with both longer aedeagal spines and a thinner female tract lining. Our results are thus consistent with a sexual arms race, which is only apparent when both male and female traits are taken into account. Importantly, our study provides rare evidence for sexually antagonistic coevolution of male and female traits at the within-species level.

scholarly journals Quantifying variation in female internal genitalia: no evidence for plasticity in response to sexual conflict risk in a seed beetle

2021 ◽  
Vol 288 (1954) ◽  
pp. 20210746
Author(s):  
Blake W. Wyber ◽  
Liam R. Dougherty ◽  
Kathryn McNamara ◽  
Andrew Mehnert ◽  
Jeremy Shaw ◽  
...  
Keyword(s):  
Social Environment ◽  
Sexual Conflict ◽  
Reproductive Tract ◽  
Callosobruchus Maculatus ◽  
Dimensional Space ◽  
Female Reproductive Tract ◽  
Female Resistance ◽  
The Social ◽  
Low Levels ◽  
Seed Beetles

Sexually antagonistic coevolution can drive the evolution of male traits that harm females, and female resistance to those traits. While males have been found to vary their harmfulness to females in response to social cues, plasticity in female resistance traits remains to be examined. Here, we ask whether female seed beetles Callosobruchus maculatus are capable of adjusting their resistance to male harm in response to the social environment. Among seed beetles, male genital spines harm females during copulation and females might resist male harm via thickening of the reproductive tract walls. We develop a novel micro computed tomography imaging technique to quantify female reproductive tract thickness in three-dimensional space, and compared the reproductive tracts of females from populations that had evolved under high and low levels of sexual conflict, and for females reared under a social environment that predicted either high or low levels of sexual conflict. We find little evidence to suggest that females can adjust the thickness of their reproductive tracts in response to the social environment. Neither did evolutionary history affect reproductive tract thickness. Nevertheless, our novel methodology was capable of quantifying fine-scale differences in the internal reproductive tracts of individual females, and will allow future investigations into the internal organs of insects and other animals.

scholarly journals Male density and rapid evolution of genital morphology in the seed beetle Callosobruchus maculatus

2016 ◽  
Author(s):  
D. M. Soper ◽  
W. L. Macy
Keyword(s):  
Reproductive Tract ◽  
Callosobruchus Maculatus ◽  
Rapid Evolution ◽  
Female Reproductive Tract ◽  
Spine Length ◽  
Seed Beetle ◽  
Male Density ◽  
Testes Size ◽  
Seven Generations ◽  
Male Genital

SummaryMale reproductive structures are known to be extremely diverse, particularly in insect taxa. Male genital structures are thought to be some of the fastest evolving traits, but the processes responsible for this pattern remain unclear. In the present study we manipulated the mating regimes of Callosobruchus maculatus, a seed beetle, to determine if male genital structures would be altered under forced monogamy and polyandry. Males in this species have an intromittent organ that contains spines that are known to puncture the female reproductive tract. We measured both testes size and genital spine length in monogamous and polyandrous treatments over seven generations. We found that testes size was not significantly different between treatments, but that genital spine length was significantly longer in the polyandrous treatment within seven generations. These results highlight the fact that evolution can occur rapidly when under strong sexual selection, a process that has been implicated in leading to morphological differences in male genitalia.

scholarly journals Copulation, genital damage and early death in Callosobruchus maculatus

2006 ◽  
Vol 274 (1607) ◽  
pp. 247-252 ◽  
Author(s):  
Paul E Eady ◽  
Leticia Hamilton ◽  
Ruth E Lyons
Keyword(s):  
Reproductive Tract ◽  
Callosobruchus Maculatus ◽  
Seminal Fluid ◽  
Negative Impact ◽  
Early Death ◽  
Female Reproductive Tract ◽  
Mating Frequency ◽  
Trade Off ◽  
Female Longevity ◽  
Fluid Transfer

Antagonistic sexual coevolution stems from the notion that male and female interests over reproduction are in conflict. Such conflicts appear to be particularly obvious when male genital armature inflicts damage to the female reproductive tract resulting in reduced female longevity. However, studies of mating frequency, genital damage and female longevity are difficult to interpret because females not only sustain more genital damage, but also receive more seminal fluid when they engage in multiple copulations. Here, we attempt to disentangle the effects of genital damage and seminal fluid transfer on female longevity in the beetle Callosobruchus maculatus (Coleoptera: Bruchidae). Males copulating for the sixth time in succession inflicted greater levels of genital damage, but transferred smaller ejaculates in comparison with virgin males. The number of copulations performed by males was negatively related to female fecundity and positively related to female longevity, suggesting a trade-off between fecundity and longevity. However, inclusion of fecundity as a covariate revealed sperm and/or seminal fluid transfer to have a negative impact on female longevity above that caused by the fecundity–longevity trade-off. The consequences of multiple copulations on female longevity were examined. Females that mated twice laid more eggs and died sooner than those that mated once. However, incorporation of fecundity as a covariate into our statistical model removed the effect of female mating frequency on female longevity, indicating that double-mated females suffer greater mortality owing to the trade-off between fecundity and longevity. Males of this species are known to transfer very large ejaculates (up to 8% of their body weight), which may represent a significant nutritional benefit to females. However, the receipt of large ejaculates appears to carry costs. Thus, the interpretation of multiple mating experiments on female longevity and associated functional explanations of polyandry in this species are likely to be complex.

scholarly journals Rapid evolution of reproductive proteins in abalone and Drosophila

2006 ◽  
Vol 361 (1466) ◽  
pp. 261-268 ◽  
Author(s):  
Tami M Panhuis ◽  
Nathaniel L Clark ◽  
Willie J Swanson
Keyword(s):  
Protein Evolution ◽  
Sexual Conflict ◽  
Reproductive Tract ◽  
Rapid Evolution ◽  
Theoretical Data ◽  
Pathogen Resistance ◽  
Accessory Gland ◽  
Female Reproductive Tract ◽  
Reproductive Proteins ◽  
Accessory Gland Proteins

Observations from different taxa, including plants, protozoa, insects and mammals, indicate that proteins involved in reproduction evolve rapidly. Several models of adaptive evolution have been proposed to explain this phenomenon, such as sexual conflict, sexual selection, self versus non-self recognition and pathogen resistance. Here we discuss the potential role of sexual conflict in the rapid evolution of reproductive genes in two different animal systems, abalone ( Haliotis ) and Drosophila . In abalone, we reveal how specific interacting sperm–egg proteins were identified and discuss this identification in the light of models for rapid protein evolution and speciation. For Drosophila , we describe the genomic approaches taken to identify male accessory gland proteins and female reproductive tract proteins. Patterns of protein evolution from both abalone and Drosophila support the predicted patterns of rapid protein evolution driven by sexual conflict. We stress however that other selective pressures may contribute to the rapid evolution that is observed. We conclude that the key to distinguishing between sexual conflict and other mechanisms of protein evolution will be an integration of genetic, experimental and theoretical data.

scholarly journals The genetic architecture of sexual conflict: male harm and female resistance in Callosobruchus maculatus

2010 ◽  
Vol 24 (2) ◽  
pp. 449-456 ◽  
Author(s):  
L. GAY ◽  
E. BROWN ◽  
T. TREGENZA ◽  
D. PINCHEIRA-DONOSO ◽  
P. E. EADY ◽  
...  
Keyword(s):  
Sexual Conflict ◽  
Genetic Architecture ◽  
Callosobruchus Maculatus ◽  
Female Resistance

scholarly journals Conspecific sperm precedence in Callosobruchus subinnotatus (Coleoptera: Bruchidae): mechanisms and consequences

2007 ◽  
Vol 274 (1612) ◽  
pp. 983-988 ◽  
Author(s):  
Paul F Rugman-Jones ◽  
Paul E Eady
Keyword(s):  
Sexual Selection ◽  
Gene Flow ◽  
Sperm Competition ◽  
Reproductive Tract ◽  
Callosobruchus Maculatus ◽  
Female Reproductive Tract ◽  
Sperm Precedence ◽  
Male And Female ◽  
Mating Order ◽  
Callosobruchus Subinnotatus

Conspecific sperm precedence (CSP) has been identified as an important post-copulatory, pre-zygotic mechanism that can act to reduce gene flow between populations. The evolution of CSP is thought to have arisen as a by-product of male and female coevolution in response to intraspecific post-copulatory sexual selection. However, little is known about the mechanisms that generate CSP. When Callosobruchus subinnotatus females copulate with both C. subinnotatus and Callosobruchus maculatus males, regardless of mating order, the majority of eggs are fertilized by conspecific sperm. The low number of heterospecific fertilizations does not result from general differences in the viability of sperm in the female reproductive tract, as heterospecific sperm fertilized equivalent numbers of eggs as conspecific sperm in the absence of sperm competition. Instead, CSP results from disadvantages to heterospecific sperm that are manifest only when in competition with conspecific sperm. CSP in C. subinnotatus appears to result from two, not mutually exclusive, mechanisms. First, conspecific sperm are better able to displace heterospecific sperm from female storage. Second, conspecific sperm achieve disproportionately higher numbers of fertilizations relative to their proportional representation in the fertilization set. Thus, we provide evidence of differential sperm use from the female spermatheca.

scholarly journals The seminal coagulum favours passage of fast-moving sperm into the uterus in the black-handed spider monkey

Reproduction ◽  
2008 ◽  
Vol 136 (4) ◽  
pp. 411-421 ◽  
Author(s):  
Leonor Hernández-López ◽  
Ana Lilia Cerda-Molina ◽  
Denisse L Páez-Ponce ◽  
Ricardo Mondragón-Ceballos
Keyword(s):  
Sperm Competition ◽  
Sexual Conflict ◽  
Reproductive Tract ◽  
Methodological Approach ◽  
Female Reproductive Tract ◽  
Spider Monkey ◽  
Menstrual Phase ◽  
Sperm Survival ◽  
And Migration ◽  
Physiological And Biochemical

In addition to gametes, mammalian internal fertilisation has required the evolution of assorted anatomical, physiological and biochemical devices to deal with intra- and inter-sexual conflict such as sperm competition and female cryptic choice respectively. The seminal coagulum of primates and other mammals is viewed as one of such devices. Among primates, the seminal coagulum characteristically occurs in multi-male and multi-female species, leading us to suppose that it intervenes in sperm competition. However, it can also provide cues to the female reproductive tract about male desired or undesired traits, and therefore deter or favour sperm survival and migration. The present work investigates whether the seminal coagulum of the black-handed spider monkey enhances sperm fertilisation chances by improving the female reproductive tract conditions, and if the female reproductive tract is ‘blind’ to semen or behaves selectively towards ejaculates of different males. A series of artificial inseminations were done in five females, using the ejaculates of three different males, one at a time, and measuring the presence of distinct types of sperm inside the uteri at 10, 30 and 60 min following the insemination. The presence of coagulum, menstrual phase, and male and female identity only affected fast, straight-moving sperm, with larger amounts of fast sperm appearing inside the uteri when ejaculates had seminal coagulum, as well as when in the periovulatory phase. There was great intra-uterine fast-sperm variation regarding which male's semen inseminated which female. The results provide evidence to account for sexual conflict in the spider monkey as well as a methodological approach to this kind of study.

Effect of Contraceptive Steroids on the Endometrium of Guinea Pig: SEM study

1977 ◽  
Vol 35 ◽  
pp. 668-669
Author(s):  
Mai M. Said ◽  
Ramesh K. Nayak ◽  
Randall E. McCoy
Keyword(s):  
Guinea Pig ◽  
Reproductive Tract ◽  
Three Dimensional ◽  
Female Reproductive Tract ◽  
Human Female ◽  
Surface Ultrastructure ◽  
Transmission Electron ◽  
Sem Study ◽  
Uterine Mucosa ◽  
Group 1

Burgos and Wislocki described changes in the mucosa of the guinea pig uterus, cervix and vagina during the estrous cycle investigated by transmission electron microscopy. More recently, Moghissi and Reame reported the effects of progestational agents on the human female reproductive tract. They found drooping and shortening of cilia in norgestrel and norethindrone- treated endometria. To the best of our knowledge, no studies concerning the effects of mestranol and norethindrone given concurrently on the three-dimensional surface features on the uterine mucosa of the guinea pig have been reported. The purpose of this study was to determine the effect of mestranol and norethindrone on surface ultrastructure of guinea pig uterus by SEM.Seventy eight animals were used in this study. They were allocated into two groups. Group 1 (20 animals) was injected intramuscularly 0.1 ml vegetable oil and served as controls.

Surface ultrastructure of danazol treated rat endometrium: A SEM study

1983 ◽  
Vol 41 ◽  
pp. 556-557
Author(s):  
R.P. Apkarian ◽  
J.S. Sanfilippo
Keyword(s):  
Cross Sections ◽  
Reproductive Tract ◽  
Preliminary Investigation ◽  
Breast Disease ◽  
Distal Segment ◽  
Uterine Horn ◽  
Female Reproductive Tract ◽  
Ultrastructural Changes ◽  
Cycle Phase ◽  
Sprague Dawley

The synthetic androgen danazol, is an isoxazol derivative of ethisterone. It is utilized in the treatment of endometriosis, fibrocystic breast disease, and has a potential use as a contraceptive. A study was designed to evaluate the ultrastructural changes associated with danazol therapy in a rat model. The preliminary investigation of the distal segment of the rat uterine horn was undertaken as part of a larger study intended to elucidate the effects of danazol on the female reproductive tract.Cross-sections (2-3 mm in length) of the distal segment of the uterine horn from sixteen Sprague-Dawley rats were prepared for SEM. Ten rats in estrus served as controls and six danazol treated rats were noted to have alterations of the estrus cycle i.e. a lag in cycle phase or noncycling patterns. Specimens were fixed in 3% glutaraldehyde in 0.05M phosphate buffer containing CaCl2 at pH 7.0-7.4 and chilled to 4°C. After a brief wash in distilled water, specimens were passed through a graded series of ethanol, critical point dryed in CO2 from absolute ethanol, and coated with 6nm Au. Observations were made with an IS1-40 SEM operated at 15kV.

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