Ineffective Maternal Care of a Subsocial Bug against a Nymphal Parasitoid: a Possible Consequence of Specialization to Predators

Authors

  • Shin-ichi Kudo

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    1. Laboratory of Applied Zoology, Faculty of Agriculture, Hokkaido University, Sapporo
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      Kudo, S. 1996: Ineffective maternal care of a subsocial bug against a nymphal parasitoid: a possible consequence of specialization to predators. Ethology 102, 227–235.


Shin-ichi Kudo, Laboratory of Applied Zoology, Faculty of Agriculture, Hokkaido University, Sapporo, 060 Japan

Abstract

In the subsocial bug Elasmucha putoni, females lay egg masses on leaves of fruit-bearing wild mulberry trees. Parent females invariably remained straddling their offspring until the offspring moulted to the second instar on natal leaves. Thereafter, the females usually settled on the stem of shoots which harboured second-or-later-instar nymphs feeding on fruit or aggregating on leaves, and faced toward the base of the shoot. To evaluate the effectiveness of maternal attendance on parasitism of nymphs by a braconid wasp, I divided the boughs of each mulberry tree into two experimental groups: a single bough which was isolated from the others by Tanglefoot treatments and on which guarding females were removed from broods before the second instar, and other boughs on which broods were left intact as controls. The experiments showed that nymphal parasitism was not affected by the presence of females. The position and orientation of females attending second-or-later-instar nymphs is probably effective for detecting predators approaching the nymphs by walking along the stem; however, this posture may prevent the females from detecting parasitoids, which fly and land directly on plant parts close to the nymphs. The ineffectiveness of the females in providing defence against the parasitoid is possibly associated with a specialization of the attending posture to pedestrian predators: a parental defensive behaviour specific to these predators may make the offspring more vulnerable to the parasitoid.

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