Lifetime reproductive effort is equal between the sexes in seed beetles (Callosobruchus maculatus): dispelling the myth of the cheap male

2016 ◽  
Vol 29 (4) ◽  
pp. 387-396 ◽  
Author(s):  
James D. Wagner ◽  
Ajibola Bakare
Keyword(s):  
Reproductive Effort ◽  
Callosobruchus Maculatus ◽  
Seed Beetles

scholarly journals Thermal Preferences of Cowpea Seed Beetles (Callosobruchus maculatus): Effects of Sex and Nuptial Gift Transfers

Insects ◽  
2021 ◽  
Vol 12 (4) ◽  
pp. 310
Author(s):  
Dariusz Krzysztof Małek ◽  
Marcin Czarnoleski
Keyword(s):  
Water Balance ◽  
Callosobruchus Maculatus ◽  
Thermal Environment ◽  
Nuptial Gift ◽  
Thermal Preference ◽  
Nuptial Gifts ◽  
Insect Performance ◽  
Evaporative Water ◽  
Thermal Preferences ◽  
Seed Beetles

The thermal environment influences insect performance, but the factors affecting insect thermal preferences are rarely studied. We studied Callosobruchus maculatus seed beetles and hypothesized that thermal preferences are influenced by water balance, with individuals with limited water reserves preferring cooler habitats to reduce evaporative water loss. Adult C. maculatus, in their flightless morph, do not consume food or water, but a copulating male provides a female with a nuptial gift of ejaculate containing nutrients and water. We hypothesized that gift recipients would prefer warmer habitats than gift donors and that both sexes would plastically adjust their thermal preferences according to the size of the transferred gift. We measured the thermal preference in each sex in individuals that were mated once or were unmated. In the mated group, we measured the sizes of the nuptial gifts and calculated proportional body mass changes in each mate during copulation. Supporting the role of water balance in thermal preference, females preferred warmer habitats than males. Nevertheless, thermal preferences in either sex were not affected by mating status or gift size. It is likely that high rates of mating and gift transfers in C. maculatus living under natural conditions promoted the evolution of constitutive sex-dependent thermal preferences.

Colonization of Marginal Host Plants by Seed Beetles (Coleoptera: Chrysomelidae): Effects of Geographic Source and Genetic Admixture

2020 ◽  
Vol 49 (4) ◽  
pp. 938-946
Author(s):  
Frank J Messina ◽  
Alexandra M Lish ◽  
Amy Springer ◽  
Zachariah Gompert
Keyword(s):  
Callosobruchus Maculatus ◽  
Larval Survival ◽  
Genetic Admixture ◽  
Parental Line ◽  
Long Distance ◽  
Asian Populations ◽  
Long Distance Transport ◽  
Novel Host ◽  
Colonization Success ◽  
Seed Beetles

Abstract The ability to adapt to a novel host plant may vary among insect populations with different genetic histories, and colonization of a marginal host may be facilitated by genetic admixture of disparate populations. We assembled populations of the seed beetle, Callosobruchus maculatus (F.), from four continents, and compared their ability to infest two hosts, lentil and pea. We also formed two cross-continent hybrids (Africa × N.A. and Africa × S.A.). In pre-selection assays, survival was only ~3% in lentil and ~40% in pea. For three replicate populations per line, colonization success on lentil was measured as cumulative exit holes after 75–175 d. On pea, we estimated the change in larval survival after five generations of selection. Females in all lines laid few eggs on lentil, and survival of F1 larvae was uniformly <5%. Subsequently, however, the lines diverged considerably in population growth. Performance on lentil was highest in the Africa × N.A. hybrid, which produced far more adults (mean > 11,000) than either parental line. At the other extreme, Asian populations on lentil appeared to have gone extinct. The Africa × N.A. line also exhibited the highest survival on pea, and again performed better than either parent line. However, no line displayed a rapid increase in survival on pea, as is sometimes observed on lentil. Our results demonstrate that geographic populations can vary substantially in their responses to the same novel resource. In addition, genetic admixtures (potentially caused by long-distance transport of infested seeds) may facilitate colonization of an initially poor host.

scholarly journals Kin but less than kind: within-group male relatedness does not increase female fitness in seed beetles

2019 ◽  
Vol 286 (1910) ◽  
pp. 20191664 ◽  
Author(s):  
Elena C. Berg ◽  
Martin I. Lind ◽  
Shannon Monahan ◽  
Sophie Bricout ◽  
Alexei A. Maklakov
Keyword(s):  
Sexual Conflict ◽  
Callosobruchus Maculatus ◽  
Lifetime Reproductive Success ◽  
Cognitive Error ◽  
Individual Fitness ◽  
Adaptive Mechanisms ◽  
Female Survival ◽  
Reproductive Part ◽  
Seed Beetles

Theory maintains within-group male relatedness can mediate sexual conflict by reducing male–male competition and collateral harm to females. We tested whether male relatedness can lessen female harm in the seed beetle Callosobruchus maculatus . Male relatedness did not influence female lifetime reproductive success or individual fitness across two different ecologically relevant scenarios of mating competition. However, male relatedness marginally improved female survival. Because male relatedness improved female survival in late life when C. maculatus females are no longer producing offspring, our results do not provide support for the role of within-group male relatedness in mediating sexual conflict. The fact that male relatedness improves the post-reproductive part of the female life cycle strongly suggests that the effect is non-adaptive. We discuss adaptive and non-adaptive mechanisms that could result in reduced female harm in this and previous studies, and suggest that cognitive error is a likely explanation.

scholarly journals Epigenetic Control of Temperature-Dependent Female Reproductive Life History Trade-Offs in Seed Beetles, Callosobruchus maculatus

2021 ◽  
Author(s):  
Beth Anne McCaw ◽  
Aoife M Leonard ◽  
Tyler J Stevenson ◽  
Lesley T Lancaster
Keyword(s):  
Dna Methylation ◽  
Life History ◽  
Callosobruchus Maculatus ◽  
Global Environmental Change ◽  
The Body ◽  
Temperature Dependent ◽  
Trade Offs ◽  
Reproductive Life ◽  
Seed Beetles ◽  
Reproductive Life History

Many species are threatened by climate change and must rapidly respond to survive changing environments. Epigenetic modifications, such as DNA methylation, can facilitate plastic responses by regulating gene expression in response to environmental cues. Understanding epigenetic responses is therefore essential for predicting species’ ability to rapidly adapt in the context of global environmental change. Here, we investigated the functional significance of DNA methylation on temperature-dependent life history in seed beetles, Callosobruchus maculatus. We assessed changes in DNA methyltransferase (Dnmt1 and Dnmt2) expression levels under ambient conditions and thermal stress, and reproductive performance following artificially-induced epimutation via 3-aminobenzamide (3AB) and Zebularine (Zeb), at a range of ambient and warmer temperatures over two generations. We found that Dnmt1 and Dnmt2 were greatly expressed in females, throughout the body, and exhibited temperature-dependence; in contrast, Dnmt expression was minimal in males. Epimutation led to shifts in female reproductive life history trade-off allocation, and differentially altered thermal optima of fecundity and offspring viability. This study revealed the optimal allocation strategy among these fitness components is temperature-dependent, and trade-offs become increasingly difficult to resolve epigenetically under more extreme warming. Results suggest that epigenetic mechanisms are strongly implicated in, and perhaps limiting of, invertebrate life history responses to temperature change. Further investigation will reveal targeted DNA methylation patterns and specific loci associated with temperature-dependent life history trade-offs in seed beetles and other invertebrates.

scholarly journals Effects of early and late life environments on ageing

2021 ◽  
Author(s):  
Krish Sanghvi ◽  
Maider Iglesias-Carrasco ◽  
Felix Zajitscheck ◽  
Loeske Kruuk ◽  
Megan Head
Keyword(s):  
Thermal Stress ◽  
Life History Traits ◽  
Callosobruchus Maculatus ◽  
Single Point ◽  
Reproductive Traits ◽  
Late Life ◽  
Age Dependent ◽  
Developmental Conditions ◽  
Seed Beetles ◽  
Integrated Study

Early and late life environments can interact in complex ways to influence the fitness of individuals. Most studies investigating effects of the environment on fitness focus on environments experienced and traits expressed at a single point in an organism's life. However, environments vary with time, thus the environments organisms experience at different ages may interact to affect how traits change throughout life. Here, we test whether thermal stress experienced during development leads individuals to cope better with thermal stress as adults. We manipulated temperature during both development and adulthood and measured a range of life-history traits, including senescence, in male and female seed beetles, Callosobruchus maculatus. We found that favourable developmental conditions increased reproductive performance of females (i.e. silver-spoon effects). In contrast, non-reproductive traits such as lifespan and survival senescence were only affected by adult environments- high adult temperatures decreased longevity and survival. Additionally, developmental and adult environments interacted to affect age-dependent changes in male weight. Overall, our results show that effects of early and late environments can be both sex- and trait- specific, and that a full understanding of how environments interact to affect fitness and ageing requires the integrated study of conditions experienced during different stages of ontogeny.

scholarly journals X-ray micro-CT scanning reveals temporal separation of male harm and female kicking during traumatic mating in seed beetles

2017 ◽  
Vol 284 (1856) ◽  
pp. 20170550 ◽  
Author(s):  
Liam R. Dougherty ◽  
Leigh W. Simmons
Keyword(s):  
Callosobruchus Maculatus ◽  
Ct Scanning ◽  
Three Dimensions ◽  
Micro Ct ◽  
Temporal Separation ◽  
X Ray ◽  
Seed Beetle ◽  
Proximate Mechanisms ◽  
Fitness Consequences ◽  
Seed Beetles

In the seed beetle Callosobruchus maculatus , the male intromittent organ is covered in sharp spines that pierce the female copulatory tract wall during mating. Although the fitness consequences of traumatic mating are well studied in this species, we know much less about how the male and female genitalia interact during mating. This is partly due to the fact that genital interactions occur primarily inside the female, and so are difficult to observe. In this study, we use X-ray micro-CT scanning to examine the proximate mechanisms of traumatic mating in C. maculatus in unprecedented detail. We show that this technique can be used to identify female tissue damage before the melanization of wound sites. We visualize the positioning of the male intromittent organ inside the female copulatory tract during mating, and show how this relates to tract wounding in three dimensions. By scanning pairs flash-frozen at different times during mating, we show that significant tract wounding occurs before the onset of female kicking. There is thus some degree of temporal separation between the onset of wounding and the onset of kicking, which supports recent suggestions that kicking is not an effective female counter-adaptation to reduce copulatory wounding in this species. We also present evidence that the sharp teeth protruding from the female tract wall are able to pierce the spermatophore as it is deposited, and may thus function to aid sperm release.

scholarly journals Kin selection and sexual conflict: male relatedness and familiarity do not affect female fitness in seed beetles

2019 ◽  
Author(s):  
Elena C. Berg ◽  
Martin I. Lind ◽  
Shannon Monahan ◽  
Sophie Bricout ◽  
Alexei A. Maklakov
Keyword(s):  
Sexual Conflict ◽  
Kin Selection ◽  
Callosobruchus Maculatus ◽  
Lifetime Reproductive Success ◽  
Individual Fitness ◽  
Adaptive Mechanisms ◽  
Female Survival ◽  
Reproductive Part ◽  
Seed Beetles

SummaryTheory maintains that kin selection can mediate sexual conflict because within-group male relatedness should reduce male-male competition, thereby reducing collateral harm to females. We tested whether male relatedness and familiarity can lessen female harm in the seed beetle Callosobruchus maculatus. Neither male relatedness nor familiarity influenced female lifetime reproductive success or individual fitness. However, male relatedness, but not familiarity, marginally improved female survival. Because male relatedness improved female survival in late life when C. maculatus females are no longer producing offspring, our results do not provide support for the role of kin selection in mediating sexual conflict. The fact that male relatedness improves the post-reproductive part of female life cycle strongly suggests that the effect is non-adaptive. We discuss adaptive and non-adaptive mechanisms that could result in reduced female harm in this and previous studies and suggest that cognitive error is a likely explanation.

scholarly journals An experimental test of temperature‐dependent selection on mitochondrial haplotypes in Callosobruchus maculatus seed beetles

2020 ◽  
Vol 10 (20) ◽  
pp. 11387-11398
Author(s):  
Elina Immonen ◽  
David Berger ◽  
Ahmed Sayadi ◽  
Johanna Liljestrand‐Rönn ◽  
Göran Arnqvist
Keyword(s):  
Experimental Test ◽  
Callosobruchus Maculatus ◽  
Temperature Dependent ◽  
Mitochondrial Haplotypes ◽  
Seed Beetles

Female seed beetles, Callosobruchus maculatus, remate for male-supplied water rather than ejaculate nutrition

2009 ◽  
Vol 63 (6) ◽  
pp. 781-788 ◽  
Author(s):  
Claudia Ursprung ◽  
Michelle den Hollander ◽  
Darryl T. Gwynne
Keyword(s):  
Callosobruchus Maculatus ◽  
Seed Beetles
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