1. Diapause is generally believed to entail costs that manifest themselves as decreased survival, rate of development, and/or reproduction after diapause completion. The present study is a first step in investigating such diapause costs in the spider mite Tetranychus urticae.2. The relationship was assessed between diapause duration and the post-diapause life-history traits of longevity and egg production, under six photoperiods at 19°C.3. The relationship between diapause duration and longevity was negative under five out of six treatments; in three cases this negative relationship was significant.4. Most evident were the negative correlations between diapause duration and rate of oviposition, peak rate of oviposition, and total egg production. These phenotypic correlations suggest that there may be a trade-off between diapause duration and postdiapause reproduction.

Mummified pistachios containing fully grown diapause larvae of Eurytoma plotnikovi Nikol'skaya (Hym., Eurytomidae) were collected in early August and late September in coastal northern Greece and subjected to various photoperiod and temperature treatments, then maintained at 19 or 26°C and a long‐day (LD 16:8 h), a changing, or a short‐day (LD 10:14 h) photoperiod until pupation. In larvae of early August (beginning of diapause) subjected for 20 weeks to 19°C under a long, a changing, or a short photophase, followed by 19°C and a long photophase, 50% of the larvae pupated after 24, 18 and 13 weeks respectively. After exposure for 20 or even 12 weeks to a short photophase and low temperatures (10 or 4°C), pupation occurred after only 7–8 weeks and was more synchronous. The ranges of temperature for diapause development and post‐diapause morphogenesis overlap. After exposure for 12 weeks to short days and low temperature, larvae of late September pupated much sooner under long days than under short days and sooner at 26° than at 19°C. E.plotnikovi depends on both temperature and photoperiod for diapause development, low temperature having a strong favourable effect on the earlier part and long day on the later part of diapause. In a few larvae of another pistachio seed wasp, Megastigmus pistaciae Walker, after a long enough period of low temperatures, diapause was terminated normally at 26°C and long days, or at 19°C and long or short days.

The solitary wasp Ampulex compressa Fabr. (Sphecidae: Hymenoptera) stings the cockroach first in the thorax and then in the neck toward the suboesophageal ganglion. The first sting results in a short lasting and completely reversible paralysis. The second sting causes an irreversible change in the behaviour: undisturbed cockroaches seem to be lethargic, and if stimulated they are able to run with speeds that equal that of control animals. RÉSUMÉ Changements dans le comportement de Periplaneta americana après piqǔres par Ampulex compressa (Hym. Sphecidae) La guěpe solitaire aculéate, Ampulex compressa Fabr. n'inflige en général à sa proie, la blatte Periplaneta americana L., que deux piqǔres: l'une thoracique au niveau d'un patte prothoracique; la seconde dans le cou, au niveau du ganglion sousoesophagien. La première piqǔre provoque une paralysie immédiate, complètement réversible en moins d'une minute. Les piqǔres doubles provoquent également une paralysie, mais réversible dans un délai de plusieurs minutes. Au surplus, la deuxième piqǔre influence irréversiblement le comportement de la blatte, qui présente un état léthargique mais est tout à fait capable de se déplacer rapidement après une stimulation des mécanorécepteurs cercaux par un léger souffle d'air au niveau du cerque.

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