Panorpa cognata

Appearance

True to their name, males have an oval-shaped genital bulb, resembling that of a scorpion’s stinger.

Reproduction

Investment in reproduction is costly for male "P. cognata", as they must “woo” females, and eventually produce a salivary mass to initiate copulation. Once copulation has begun, sperm transfer itself is costly, as well. Sperm is transferred into the female via a sperm pump, which has two thick muscles, one on either side of the pump. Nutrient availability during the larval stage affects adult body weight, and the development of the males' salivary glands. Males with restricted access to nutrients in larval stage have reduced mating success compared to those of good condition with access to greater amounts of nutrients in the larval stage. Males of lower condition have less resources to produce nuptial gifts, resulting in smaller salivary masses, shorter mating duration, and less sperm transferred. To counteract their poor condition, males tend to have a longer premating duration than those of higher condition. Males of higher condition tend to have shorter premating periods and larger nuptial gifts. Premating rituals do not always finish in successful copulation, females abandon the male courting her for better, more attractive mates. Male "P. cognata" regulate their mating investment according to the amount of sperm competition. Female "P. cognata" store sperm from each male she mates with, and each consecutive mate has the ability to assess how much sperm she is storing, thus down-adjusting the male's investment in copulation with a female who has more sperm stored.The condition of female "P. cognata", dictated by nutritional availability in the larval stage, is positively correlated with the number of sperm transferred during copulation, with males transferring sperm to females in good condition at a faster rate than they would transfer to females of poor condition. Females control the duration of copulation, which is directly affected by the size of the salivary nuptial gift provided by the male. The species, "P. cognata", benefits as a whole from the female mating with multiple males and ingesting multiple salivary nuptial gifts, as each salivary mass a female ingests has been shown to have, on average, a positive 8% increase on the number of eggs she lays. The duration of copulation impacts the female's length of time between rematings; longer copulations result in a longer period between matings.