Water intake by the adult mayfly Epeorus ikanosis (Ephemeroptera: Heptageniidae) and its effect on their longevity

Abstract

Water drinking habits during flight in adult mayflies of Epeorus ikanonis Takahashi were observed and the effect of water intake on their longevity was examined. The study was carried out in a mountain stream in western Japan. Adult males collected a water droplet under the head capsule while alighting on the water surface and consumed it after moving to nearby riparian vegetation. The amount of water intake was experimentally estimated to be 9.7% of the bodyweight for males. Although females did not show the water drinking behavior in the field, they imbibed as much as 5.5 % of the bodyweight of water in an experimental situation. Morphological observation of the mouthparts revealed that the water was drawn in through the pits at the base of the labrum. In the field caging experiment, males with a water supply had a substantially longer life span than those without. Increase in adult life span by drinking water was less marked in females. Multiple copulation was observed in both sexes during the experiment. The water drinking behavior of the males may closely relate to mating success through increased longevity. Variation in the longevity of adult mayflies was discussed with regard to the possibility of water intake.

The structure of the foregut and midgut of nymphs, subimagos and imagos of Cloeon dipterum (Ephemeroptera) and the functions of the gut of adult mayflies

“…Despite these observations it does not, however, seem likely that there is active or frequent uptake of liquid by imagos of Cloeon, both because the surface of the mouth area is so water-repellent and because the stance of the imago, as in other may¯y species, makes it very dif®cult for the mouth to be brought into contact with the substratum or even with adjacent foliage. Takemon (1993) has, however, described imagos of Epeorus ikanonis alighting momentarily on the surface of a stream and picking up water droplets: but his conclusion, that because droplets disappear from the head region they must enter the gut, fails to take into account the alternative possibility that the droplets disperse as a thin ®lm over the outer surface of the imago, the process so frequently observed in the present study.…”

Reproductive behavior and morphology of Paraleptophlebia spinosa (Ephemeroptera: Leptophlebiidae): implications of variation in copula duration

“…On the other hand, Flecker et al (1988) argued that swarming males of a heptageniid mayfly, Epeorus longimanus, are under strong intermale competition. This conclusion was supported by observation of relatively long adult life and multiple copulation by males in another heptageniid, Epeorus ikanonis (Takemon 1993).…”

“…A notable exception is a ground-copulating heptageniid mayfly, Epeorus ikanonis, for which female multiple copulation was confirmed. The females successively mated with different males in cages (Takemon 1993), and observation in the field confirmed that 12% of all females engaged in multiple copulation within a restricted period of 13 min before oviposition (Takemon 1990a).…”

“…The air temperature was recorded at Okunomiya by a thermograph with remote sensors. Data on temperature and humidity at the study site throughout the study period are given in Takemon (1993).…”

A Review of Chemosensation and Related Behavior in Aquatic Insects

“…It is generally accepted that mayfly adults do not feed, although intake of water may occur ( Takemon 1993 ), and they usually live for a very short period of time. Mating, oviposition and, in some cases, dispersal are the main functions of this stage.…”