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Effects of egg availability and egg maturity on the ovipositional activity of the parasitic wasp, Coccophagus atratus
Author(s) -
DONALDSON J. S.,
WALTER G. H.
Publication year - 1988
Publication title -
physiological entomology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.693
H-Index - 57
eISSN - 1365-3032
pISSN - 0307-6962
DOI - 10.1111/j.1365-3032.1988.tb01124.x
Subject(s) - biology , aphelinidae , hymenoptera , parasitoid , zoology , honeydew , oogenesis , botany , oocyte , embryo , fishery
. Effects of egg availability on daily ovipositional activity were determined for Coccophagus atratus Compere (Hymenoptera: Aphelinidae). Females were observed for 6 h per day for their entire adult lives. Observed ovipositional activity was analysed in relation to egg maturation before and after emergence, egg depletion during oviposition and egg replenishment after oviposition. Ovipositional activity, including oviposition, inconsequential probes and searching for hosts, occurred predominantly in the first 30 min of exposure to hosts on the 2nd, 4th, 7th, 10th and 13th days after emergence. The remaining time was spent on non‐ovipositional activities (preening, drinking honeydew and sitting on the glass of the experimental arena). Peaks of ovipositional activity were associated with high numbers of mature eggs in the ovaries. Eggs that remained in the ovaries after a bout of oviposition were apparently not mature even though they had attained their maximum size. Non‐ovipositional activity continued until females had built up a reserve of about eighteen mature eggs. After each successive bout of oviposition, the rate of oogenesis slowed down. Consequently females took longer to accumulate a supply of eggs and periods of non‐ovipositional activity increased. We conclude that (1) the availability of eggs and the tendency of females to store mature eggs influences ovipositional activity, (2) full‐sized eggs are not necessarily mature, (3) future experiments with C.atratus could be restricted to days of high ovipositional activity, and (4) the terms syn‐ and pro‐ovigenic formulated by Flanders (1950) to describe apparent differences in oogenesis between various parasitic Hymenoptera do not apply to C. atratus and are therefore not universally applicable.