scholarly journals Exposure to rivals and plastic responses to sperm competition in Drosophila melanogaster

2010 ◽  
Vol 21 (2) ◽  
pp. 317-321 ◽  
Author(s):  
Amanda Bretman ◽  
Claudia Fricke ◽  
Primrose Hetherington ◽  
Rachel Stone ◽  
Tracey Chapman
Keyword(s):  
Drosophila Melanogaster ◽  
Sperm Competition ◽  
Plastic Responses

scholarly journals Plastic responses of male Drosophila melanogaster to the level of sperm competition increase male reproductive fitness

2009 ◽  
Vol 276 (1662) ◽  
pp. 1705-1711 ◽  
Author(s):  
Amanda Bretman ◽  
Claudia Fricke ◽  
Tracey Chapman
Keyword(s):  
Drosophila Melanogaster ◽  
Reproductive Success ◽  
Sperm Competition ◽  
Reproductive Fitness ◽  
Male Reproductive Success ◽  
Mating Duration ◽  
Contrast Exposure ◽  
Plastic Responses ◽  
Paternity Share

Evolutionary and plastic responses by males to the level of sperm competition (SC) are reported across widespread taxa, but direct tests of the consequences for male reproductive success in a competitive context are lacking. We varied male perception of SC to examine the effect on male competitive reproductive success and to test whether the outcomes were as predicted by theory. Exposure to rival males prior to mating increased a male's ejaculate investment (measured as mating duration); by contrast, exposure to rival males in the mating arena decreased mating duration. The results therefore suggested that SC intensity is important in shaping male responses to SC in this system, although the patterns were not strictly in accord with existing theory. We then tested whether males that responded to the level of SC had higher reproductive fitness in a competitive context. We found that males kept with rivals prior to mating again mated for longer; furthermore, they achieved significantly higher paternity share regardless of whether they were the first or second males to mate with a female. The plastic strategies employed by males therefore resulted in significantly increased reproductive success in a competitive context, even following subsequent rematings in which the majority of sperm were displaced.

scholarly journals SPERM COMPETITION AND SPERM LOSS IN DROSOPHILA MELANOGASTER FEMALES FERTILIZED BY YSX·YL/0 MALES

Genetics ◽  
1970 ◽  
Vol 64 (2) ◽  
pp. 323-335
Author(s):  
G Olivieri ◽  
G Avallone ◽  
L Pica
Keyword(s):  
Drosophila Melanogaster ◽  
Sperm Competition

scholarly journals Flexible memory controls sperm competition responses in male Drosophila melanogaster

2018 ◽  
Vol 285 (1879) ◽  
pp. 20180619 ◽  
Author(s):  
J. Rouse ◽  
K. Watkinson ◽  
A. Bretman
Keyword(s):  
Drosophila Melanogaster ◽  
Environmental Change ◽  
Sperm Competition ◽  
Learning And Memory ◽  
Mating Behaviour ◽  
Brain Structures ◽  
Plastic Behaviour ◽  
Rival Male ◽  
Lag Times ◽  
Underlying Mechanisms

Males of many species use social cues to predict sperm competition (SC) and tailor their reproductive strategies, such as ejaculate or behavioural investment, accordingly. While these plastic strategies are widespread, the underlying mechanisms remain largely unknown. Plastic behaviour requires individuals to learn and memorize cues associated with environmental change before using this experience to modify behaviour. Drosophila melanogaster respond to an increase in SC threat by extending mating duration after exposure to a rival male. This behaviour shows lag times between environmental change and behavioural response suggestive of acquisition and loss of memory. Considering olfaction is important for a male's ability to assess the SC environment, we hypothesized that an olfactory learning and memory pathway may play a key role in controlling this plastic behaviour. We assessed the role of genes and brain structures known to be involved in learning and memory. We show that SC responses depend on anaesthesia-sensitive memory, specifically the genes rut and amn . We also show that the γ lobes of the mushroom bodies are integral to the control of plastic mating behaviour. These results reveal the genetic and neural properties required for reacting to changes in the SC environment.

scholarly journals Structural variation in Drosophila melanogaster spermathecal ducts and its association with sperm competition dynamics

2020 ◽  
Vol 7 (3) ◽  
pp. 200130
Author(s):  
Ben R. Hopkins ◽  
Irem Sepil ◽  
Stuart Wigby
Keyword(s):  
Drosophila Melanogaster ◽  
Sperm Competition ◽  
Structural Variation ◽  
Reproductive Tract ◽  
Distal Portion ◽  
Mating Status ◽  
Spermathecal Duct ◽  
Male Sperm ◽  
Storage Organs ◽  
Single Mating

The ability of female insects to retain and use sperm for days, months, or even years after mating requires specialized storage organs in the reproductive tract. In most orders, these organs include a pair of sclerotized capsules known as spermathecae. Here, we report that some Drosophila melanogaster females exhibit previously uncharacterized structures within the distal portion of the muscular duct that links a spermatheca to the uterus. We find that these ‘spermathecal duct presences' (SDPs) may form in either or both ducts and can extend from the duct into the sperm-storing capsule itself. We further find that the incidence of SDPs varies significantly between genotypes, but does not change significantly with the age or mating status of females, the latter indicating that SDPs are not composed of or stimulated by sperm or male seminal proteins. We show that SDPs affect neither the number of first male sperm held in a spermatheca nor the number of offspring produced after a single mating. However, we find evidence that SDPs are associated with a lack of second male sperm in the spermathecae after females remate. This raises the possibility that SDPs provide a mechanism for variation in sperm competition outcome among females.

scholarly journals Virility does not Imply Immensity: Testis size, Accessory Gland Size and Ejaculate depletion pattern do not Evolve in Response to Experimental Manipulation of Sex Ratio in Drosophila melanogaster

2015 ◽  
Author(s):  
◽  
Zeeshan Ali Syed ◽  
N G Prasad
Keyword(s):  
Drosophila Melanogaster ◽  
Sex Ratio ◽  
Sperm Competition ◽  
Competitive Ability ◽  
Experimental Manipulation ◽  
Reproductive Organ ◽  
Accessory Gland ◽  
Testis Size ◽  
Gland Size ◽  
Competition Theory

Sperm competition theory predicts that increase in sperm competition should result in bigger male reproductive organ(s) or higher ejaculate investment. We test this idea using experimental evolution in Drosophila melanogaster. We maintained replicate populations of Drosophila under male (M) and female (F) biased sex ratio regimes for more than a hundred generations. Males in M regime have evolved higher sperm competitive ability than those in F. We measured the testes and the accessory gland size of virgin and singly mated males from the M and F populations. The M and F males do not differ in either testis or accessory gland size. Additionally, ejaculate investment is not different in the M and F males, as measured by reduction in testis and accessory gland sizes. Thus, contrary to theoretical prediction and evidence from other species, evolved differences in sperm competitive ability is not due to evolution of testis/accessory gland size or strategic ejaculate investment in these populations.

scholarly journals Female Genetic Contributions to Sperm Competition in Drosophila melanogaster

Genetics ◽  
2019 ◽  
Vol 212 (3) ◽  
pp. 789-800 ◽  
Author(s):  
Dawn S. Chen ◽  
Sofie Y. N. Delbare ◽  
Simone L. White ◽  
Jessica Sitnik ◽  
Martik Chatterjee ◽  
...  
Keyword(s):  
Nervous System ◽  
Drosophila Melanogaster ◽  
Sperm Competition ◽  
Reproductive Tract ◽  
Seminal Fluid ◽  
Association Studies ◽  
Genome Wide Association Studies ◽  
Link Type ◽  
Female Genotype ◽  
Mechanistic Basis

In many species, sperm can remain viable in the reproductive tract of a female well beyond the typical interval to remating. This creates an opportunity for sperm from different males to compete for oocyte fertilization inside the female’s reproductive tract. In Drosophila melanogaster, sperm characteristics and seminal fluid content affect male success in sperm competition. On the other hand, although genome-wide association studies (GWAS) have demonstrated that female genotype plays a role in sperm competition outcome as well, the biochemical, sensory, and physiological processes by which females detect and selectively use sperm from different males remain elusive. Here, we functionally tested 26 candidate genes implicated via a GWAS for their contribution to the female’s role in sperm competition, measured as changes in the relative success of the first male to mate (P1). Of these 26 candidates, we identified eight genes that affect P1 when knocked down in females, and showed that five of them do so when knocked down in the female nervous system. In particular, Rim knockdown in sensory pickpocket (ppk)+ neurons lowered P1, confirming previously published results, and a novel candidate, caup, lowered P1 when knocked down in octopaminergic Tdc2+ neurons. These results demonstrate that specific neurons in the female’s nervous system play a functional role in sperm competition and expand our understanding of the genetic, neuronal, and mechanistic basis of female responses to multiple matings. We propose that these neurons in females are used to sense, and integrate, signals from courtship or ejaculates, to modulate sperm competition outcome accordingly.

scholarly journals Exposure to endosulfan influences sperm competition in Drosophila melanogaster

2014 ◽  
Vol 4 (1) ◽  
Author(s):  
Snigdha Misra ◽  
Ajay Kumar ◽  
Ch. Ratnasekhar ◽  
Vandana Sharma ◽  
Mohana Krishna Reddy Mudiam ◽  
...  
Keyword(s):  
Drosophila Melanogaster ◽  
Sperm Competition
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