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Effects of photoperiod, time of year, temperature, and an insect growth regulator (fenoxycarb) on ovarian development rate in overwintering pear psylla, Cacopsylla pyricola (Foerster), were determined. Winterform pear psylla were collected from the field at intervals between October and February, and reared at 20 °C and one of three treatments: short-day photoperiod, long-day photoperiod, or short-day photoperiod + fenoxycarb. Insects were then dissected at intervals to score ovarian development. Baseline scores (i.e., ovarian development in the field on date of collection) increased very slowly between October and February. By mid-February, only about 20% of insects in the field were categorized as having postdiapause status based upon ovarian development. In the laboratory, time required for insects to reach postdiapause status decreased between the October and February collection dates. Number of days necessary for 50% of the long-day insects to reach postdiapause status was approximately 2 weeks in October, 6 days in December, and < 2 days in February. Short-day insects also required fewer than 2 days in February, but required > 2 weeks in the October and December samples. Our results suggested that insects collected in January and February had completed diapause but that ovarian development was subsequently prevented in the field by low temperatures. Fenoxycarb caused rapid ovarian development even in October-collected insects; rate of development was only slightly more rapid in the February-treated psylla.

The influence of male and female body size on copulation duration and probability of insemination was determined for Anthocoris whitei Reuter allowed to mate at two temperatures. Copulation duration decreased significantly with increasing male length or increasing relative size (male length divided by female length). Female length had no effect on copulation duration. We interrupted copulation at 20 or 40 min at both 25 and 15 °C to determine the interacting effects of male size, temperature, and copulation duration on probability of insemination. Insemination probabilities increased with increasing male size, increasing temperature, and increased duration of copulation. Large males were more successful than small males at inseminating females at cool temperatures and for severely shortened copulations. Results are consistent with the hypothesis that males of this species experience physical difficulties either in achieving intromission or in forcing sperm through the aedeagus, and that larger body size in males lessens these difficulties.

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Eight potato (Solanum tuberosum L.) lines and a control (cv. Russet Burbank) were screened for suitability to Colorado potato beetle, Leptinotarsa decemlineata (Say) (Chrysomelidae), and for defoliation levels in the field to determine whether laboratory‐obtained measures of performance are useful for predicting defoliation. Several lines caused reduced larval growth rates and survival compared to the control. Forty‐eight hour weight gains by fourth instar larvae, after adjustment for consumption rates, were reduced on three lines, suggesting that these lines had antibiosis‐like effects. Lines having very low suitability in the laboratory showed very low defoliation levels in the field, whereas lines that were highly suitable in the laboratory tended to suffer extensive defoliation in the field. Correlation analyses suggested that fourth instar growth rates or larval survival rates are useful measures for predicting defoliation in the field.

The Canadian Entomologist 130: 285 -304 (1998) All ontogenetic stases of the yew big bud mite, Cecidophyopsis psilaspis (Nalepa), from British Columbia were studied by scanning electron and light microscopy and were compared with an English population of this species. The species was redescribed from the two populations, which were found to be quite similar in general appearance and in most of the morphometric data analyzed. Spermatophores in this species are similar to those observed in other Eriophyoidea. Details of a male spermatophoric organ are described and illustrated for the first time in an eriophyoid mite. Moulting in C. psilaspis is shown to be prodehiscent. The data reported here neither support nor reject the alternative hypothesis that the first active stase is larval versus nymphal. However, to account for the ontogenetic evidence, the first active stase isherein considered larval. Marshall, V.G., M.R. Clayton et D.N. Newsom. 1998. La morphologie, l'ontogenese, et la variabilitk intraspecifique du phypopte des bourgeons d'if, Cecidophyopsis psilaspis (Acari : Eriophyidae). The Canadian Entomologist 130 : 285-304. Toutes les stases ontogtnttiques d'une population de la Colombie-Britannique du phytopte des bourgeons de l'if, le Cecidophyopsis psilaspis (Nalepa), ont Ct C exa-minCes par microscopie Clectronique a balayage et microscopie optique et compa-rCes a celles d'une population de la mCme espbce provenant d'Angleterre. Une nouvelle description de l'espbce a Ctt proposte au terme de cet examen. Les deuxpopulations se ressemblaient passablement en ce qui a trait a I'aspect gCnCral et a la majorit6 des donnCes morphomttriques analystes. Les spermatophores chez cette espbce sont semblables 21 ceux observCs chez les autres Eriophyoidea et sont dtcrits en dCtail et illustrCs pour la premibre fois chez un Eriophyoidea. La mue chez le C. psilaspis est de type prodChiscent. Les donnCes prksenttes ici ne confirment ni n'infirment l'hypothbse alternative selon laquelle la premibre stase active est la larve plut6t que la nymphe. Toutefois, eu Cgard aux donnCes ontogCnCtiques recueillies, la larve est considCrCe ici comme Ctant la premibre stase active.