Hatching of oothecae from female Blattella germanica exposed to hydramethylnon and boric acid baits

Autor: J. J. Zhou, G. le Patourel
Rok vydání: 1990
Předmět:
Zdroj: Entomologia Experimentalis et Applicata. 54:131-140
ISSN: 0013-8703
Popis: Adult female Blattella germanica (L.) (Dictyoptera: Blattellidae) carrying oothecae were confined in cages with bait formulations of boric acid or hydramethylnon at 90% r.h. and either 20° or 28 °C until all had been killed. Females poisoned by hydramethylnon retained their oothecae at death, while a considerable proportion of those killed by boric acid deposited their oothecae prematurely. Oothecae from both groups of insects were monitored until they either hatched or lost viability. Oothecae from both 7–14 day old adults and 14–21 day old adults poisoned with hydramethylnon showed reduced hatching relative to controls at 20° but not at 28 °C, an effect attributed to premature loss of water-exchange between oothecae and female adult during the maturation process. Fewer oothecae hatched from females poisoned with boric acid at both temperatures, and the proportion of those which did hatch was higher in the group retained by the female at death than in the group prematurely deposited. These results for the boric acid-treated females and results which showed no significant difference between the hatch of oothecae from hydramethylnon-treated females and decapitated females suggested that transfer of insecticide from treated female to oothecae was not important in reducing hatch for either compound. Reinfestation as a consequence of the failure of conventional blatticides to prevent hatching of oothecae carried by female B. germanica is discussed. Resume L'eclosion des ootheques de Blattella germanica exposees a des appâts a l'hydramethylnone et a l'acide borique Des femelles adultes de B. germanica, maintenues a 20° ou 28 °C et 90% HR, ont ete exposees, 7 a 14 jours ou 14 a 21 jours apres l'emergence a des appâts contenant de l'hydramethyinone ou de l'acide borique. Empoisonnees par l'hydramethyinone les femelles retiennent leur ootheque jusqu'a la mort, tandis que empoisonnees par l'acide borique, elles deposent leur ootheque prematurement. Toutes les ootheque des femelles empoisonnees ont ete maintenues dans les memes conditions ecologiques jusqu'a ce qu'elles eclosent ou se revelent non viables. Avec l'acide borique, une reduction des naissances a ete observee pour les ootheques des meres des 2 classes d'âges et aux 2 temperatures, ce qui n'a eu lieu qu'a la temperature basse avec l'hydramethyinone. L'effet ne semble pas du au transfert de l'insecticide de la femelle a l'ootheque et est plus probablement provoque par la fin des echanges d'eau entre la mere et l'ootheque, a la mort ou lors de l'emission prematuree. Pour les femelles traitees a l'acide borique, la proportion d'eclosion d'ootheques est plus importante chez les femelles ayant retenu leur ootheque jusqu'a la mort que chez celles qui les ont emises prematurement. Les femelles empoisonnees lors d'operations d'eradication peuvent mourir ou deposer leurs ootheques loin des zones traitees; les larves eclosant de ces ootheques peuvent maintenir la contamination.
Databáze: OpenAIRE
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