Influência da temperatura na freqüência de cópula de Anticarsia gemmatalis Hübner e Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae)

Abstract

Neotropical Entomology 37(5): 528-535 (2008) Temperature Effects on the Mating Frequency of Anticarsia gemmatalis Hüebner and Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae)ABSTRACT -This paper deals with the infl uence of temperature on the mating frequency of two lepidopterans, Anticarsia gemmatalis Hübner and Spodoptera frugiperda (J.E. Smith), which use different strategies of allocation, and with the utilization of nutrients for their reproductive activities. The insects were reared on artifi cial diets at 25ºC, and the adults were exposed to fi ve temperatures (15, 20, 25, 30, and 35ºC) to observe the infl uence of each temperature on their mating frequency, fecundity, fertility and longevity. The temperature affectedthe mating frequency of both species, being more evident at 15ºC and 35ºC, mainly for A. gemmatalis, which presented a drastic reduction on mating activities. The highest number of matings were observed from 20ºC to 30ºC, with S. frugiperda presenting mating activity (0-8) much higher than that of A. gemmatalis (0-2), but no correlation was observed among the number of matings and all other biological parameters evaluated (fecundity, fertility and longevity). However, S. frugiperda showed a positive correlation between fecundity and mating activity of females (r = 0.589; P = 0.003) at 25ºC. The highest fecundities were observed at temperatures from 20ºC to 30ºC for S. frugiperda and at 25ºC for A. gemmatalis. For both species, the longevity of males and females decreased as temperature increased.KEY WORDS: Reproduction, defoliator caterpillar, spermatophore, fecundity RESUMO -Este trabalho estudou a infl uência da temperatura na freqüência de cópula de Anticarsia gemmatalis Hübner e Spodoptera frugiperda J. E. Smith, que empregam diferentes estratégias de alocação, e a utilização de nutrientes para suas atividades reprodutivas. Os insetos foram criados em dieta artifi cial a 25ºC, sendo a infl uência da temperatura na freqüência de cópula, fecundidade, fertilidade e longevidade de adultos avaliada em cinco temperaturas (15, 20, 25, 30 e 35ºC). A temperatura afetou a freqüência de cópula de ambas as espécies, sendo o seu efeito mais evidente nas temperaturas extremas estudadas (15ºC e 35ºC), principalmente, para A. gemmatalis, que apresentou redução drástica em sua atividade de cópula. Temperaturas intermediárias (20ºC a 30ºC) permitiram o maior número de cópulas, com S. frugiperda apresentando (até oito cópulas) atividade de cópula muito superior à de A. gemmatalis (até duas cópulas). Mesmo com a variação encontrada na atividade de cópula nas diferentes temperaturas, não foi verifi cada correlação entre o número de cópulas e os demais parâmetros biológicos observados (fecundidade, fertilidade e longevidade), com exceção da fecundidade de S. frugiperda a 25ºC, que apresentou correlação positiva com a atividade de cópula nessa temperatura (r = 0,589; P = 0,003), indicando que as alterações na atividade reprodutiva desse inseto foram decorrentes, basicamente, de sua resposta à tem...

Biotic potential, fertility and life table ofSpodoptera albula (Walker) (Lepidoptera: Noctuidae), under controlled conditions

“…This percentage agrees with the 94-98% reported by Novo and generally refers to Spodoptera representatives in studies where multiple mating is known to enhance the reproductive capacity, including fertility (Kehat and Gordon 1975, Sadek 2001, Sadek and Anderson 2007, Busato et al 2008, Milano et al 2008 , respectively. For S. eridania, at 27°C, using data from Parra et al (1977) and considering a sex ratio of 0.5 or 1:1, gives roughly 6.6 x 10 23 and 6.8 x 10…”

“…Our results, together with the various publications that present a positive relationship between fecundity and fertility, indicate that if somehow the number of copulations were anticipated and increased, by using multiple couples per cage (Milano et al 2008), the fecundity of S. albula could be even greater.…”

“…The positive relationship between fecundity and number of copulations has been documented for S. exigua (Rogers and Marti Jr 1996), S. frugiperda (Snow et al 1970, Rogers and Marti Jr 1994, Milano et al 2008 (Ward andLandolt 1995, Landolt 1997). The use of material gained from spermatophores for the production of eggs is one of the demonstrated benefits of "re-mating" which is received by females of other Lepidoptera (not Noctuidae) (i.e.…”

“…Regarding the absence of copulation in some S. albula pairs, these same authors reported that in some S. frugiperda cohorts more than 20% of the females did not mate, while in other cohorts more than 20% of couples performed more than two copulations. Moreover, considering that Milano et al (2008), using 25 S. frugiperda pairs per cage, obtained a mean of over three spermatophores per female with a maximum of six, at 25°C, it is expected that a greater number of S. albula individuals per cage also increases the number of copulations.…”

“…In this way, when a single couple of S. frugiperda was used (Murúa et al 2008) in comparison to multiple couples per cage (Milano et al 2008), it caused a reduction in the mating number, in turn, it was associated with an increase in longevity and in the pre-oviposition period, leading to a decrease in fecundity and fertility.…”