Sperm production in an extremophile fish, the cave molly (Poecilia mexicana, Poeciliidae, Teleostei)

Abstract

A prominent trade-off in life history theory and evolution balances the costs of reproduction with those of basic somatic needs. Hence, reproductive efforts may be reduced in environments where additional energy is required for somatic maintenance. Here, we investigated male sperm stores in Atlantic mollies (Poecilia mexicana) from a sulfidic cave and several sulfidic and non-sulfidic surface habitats. We found significant differences among populations in the number of sperm stripped per male, which was also correlated with differences in gonad weights. The largest sperm stores were detected in males from non-sulfidic surface creeks, while males from a partially sulfidic surface system had lower sperm counts, and males from completely sulfidic systems, surface as well as subterranean, had even fewer available sperm. We conclude that the extreme environmental conditions in sulfidic habitats appear to constrain male sperm production, since hydrogen sulfide as a naturally occurring toxin requires energy-demanding adaptations. Furthermore, we examined sperm counts of lab-reared cave and surface mollies in response to energy limitation. Males from stock populations were placed under high and low food treatments for a 2-week period and then stripped of sperm. Sperm counts of surface mollies tended to be reduced by low food availability, whereas sperm counts of cave mollies did not significantly vary between food treatments, which likely points towards a higher starvation resistance in cave mollies.

Toxic hydrogen sulphide and dark caves: pronounced male life-history divergence among locally adapted Poecilia mexicana (Poeciliidae)

“…, 2002; Evans et al. , 2003) and parallels the reduced sperm count reported in CdA males by Franssen et al. (2008).…”

“…Then again, a reduction in sperm count, sexual behaviours and male–male aggression has also been reported for EA (Plath et al. , 2003; Franssen et al. , 2008), but GSI is even higher in EA than in RGU.…”

Morphological evidence for limited sperm production in the enigmatic Tasmanian cave spiderHickmania troglodytes(Austrochilidae, Araneae)

“…It is known for several taxa that extreme habitats can alter reproduction (as reported for cave fishes: Franssen et al. ). As sperm production is costly, having only a brief period of spermatogenesis might be an ideal way to overcome high energy expenditures.…”

“…For example, the reproductive system might be altered as in fishes, where cave species produce fewer but larger eggs (Pouilly & Miranda ) or have lower sperm counts (Franssen et al. ). The same is true in cave amphipods, which show annual, but not seasonal, changes in sperm production (Jegla ).…”

The Adipokinetic Hormone Receptor Modulates Sexual Behavior, Pheromone Perception and Pheromone Production in a Sex-Specific and Starvation-Dependent Manner in Drosophila melanogaster

“…Keywords: adipokinetic hormone, courtship, pheromones, cis-vaccenyl acetate, nutritional status, sexual dimorphism INTRODUCTION Food availability and food deprivation affect the reproduction of a wide range of animals including mammals, fishes, insects, or spiders, through acting on both physiological and behavioral traits (Franssen et al, 2008;Martin et al, 2008;Moskalik and Uetz, 2011). Hormones that are regulated by food intake control many of these reproductive traits (Kauffman et al, 2006;Martin et al, 2008).…”