Ecological Characteristics of Oviposition and Eggs in the Antlions Living in Seaside Dunes : Tolerance to High Temperature (Neuroptera : Myrmeleontidae)

概要

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Antlions living in seaside dunes lay their eggs at night during mid-summer below the sand-surface, where the temperature becomes extremely high in the daytime. We first observed the oviposition behavior and examined the number of eggs laid per night by Myrmeleon bore and Distoleon contubernalis. The larva of the former species is a pit builder but the latter is not. Most female antlions of both species came to the oviposition site from 8 : 00p.m. to 9 : 00p.m. They oviposited eggs one by one at the depth of ca. 7.5mm (M. bore) or 10mm (D. contubernalis) in the sand. The average number of eggs laid per night per female was 16.5 for M. bore and 17.3 for D. contubernalis. Secondly, we examined their hatching rates under the conditions of constant or changing temperature in order to know how their eggs are tolerant to high temperature. Under a constant temperature of 37.5℃, most eggs of D. contubernalis hatched successfully, while no eggs of M. bore hatched. At the temperature of 40℃ none of the eggs of either species hatched. Under quasi-natural conditions, the hatching rate became lower as the total duration of exposure to a temperature above 40℃ became longer. These results suggest that the female antlion selects a thermally suitable oviposition site by using an environmental indicator.
日本昆虫学会の論文
2001-03-25