Sperm production and mating potential of males after a cold shock on pupae of the parasitoid wasp Dinarmus basalis (Hymenoptera: Pteromalidae)

• Published in: Journal of insect physiology 2007-10, Vol.53 (10), p.1008-1015
• Main Authors: Lacoume, Sandrine, Bressac, Christophe, Chevrier, Claude
• Format: Article
• Language: English
• Subjects: age; Age Factors; Animals; cold stress; Cold Temperature; Dinarmus basalis; Female; Hymenoptera; insect reproduction; Life Sciences; Male; male fitness; Male mating ability; Male sperm supply; males; mating behavior; mating competitiveness; multiple mating; parasitoids; Pteromalidae; pupae; Pupal development; Reproduction - physiology; Reproductive Biology; Sexual reproduction; Sperm Count; Sperm stock; sperm supply; spermatogenesis; spermatozoa; Spermatozoa - physiology; Thermal stress; Wasps - physiology
• ISSN: 0022-1910; 1879-1611
• DOI: 10.1016/j.jinsphys.2007.05.006

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 (1 h at −18 °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.