Sperm production and mating potential of males after a cold shock on pupae of the parasitoid wasp Dinarmus basalis (Hymenoptera: Pteromalidae).
For ectothermic species, temperature is a key environmental factor influencing several aspects of their physiology and ecology, acting particularly on reproduction. To measure the consequences of a severe thermal stress during development on male reproduction, a cold shock (1h at -18 degrees C) was tested on Dinarmus basalis pupae. D. basalis (Hymenoptera: Pteromalidae) is a parasitoid wasp in which sperm management in both male and female is of prime importance. After a cold shock, developmental success was reduced, with a quarter of cold-shocked males not emerging correctly. The stress effects were estimated at the level of sperm stock in seminal vesicles of males at different ages and on the ability of 2-day-old males to access females in single and multiple mating and in male-male competition. Cold-shocked males had a reduced sperm stock compared to control males and this difference persisted with age. The rate of sperm production was similar in both groups. The consequences of a cold shock on male reproductive ability were perceptible in multiple mating and male-male competition but not in single mating. Cold-shocked males were at a disadvantage, inseminating fewer females and copulating less frequently. Finally, male pupae of D. basalis were able to withstand severe temperature stresses and their reproductive functions were partially preserved.
Lacoume
Sandrine
S
Institut de Recherche sur la Biologie de l'Insecte, UMR CNRS 6035, Université de Tours, 37200, Tours, France. sandrine.lacoume@etu.univ-tours.fr
Bressac
Christophe
C
Chevrier
Claude
C
D000367:Age Factors; D000818:Animals; D003080:Cold Temperature; D005260:Female; D008297:Male; D012098:Reproduction / Q000502:physiology; D013076:Sperm Count; D013094:Spermatozoa / Q000502:physiology*; D014863:Wasps / Q000502:physiology*