Development of Hypsipyla grandella (Zeller) (Lepidoptera: Pyralidae) in response to constant temperatures

Abstract

C. O estudo foi realizado em câmaras climáticas, com umidade de 80-90% e fotoperíodo de 8L:16D. Após a eclosão, as larvas foram alimentadas com folhas tenras de cedro (Cedrela odorata) e inspecionados a cada 24h para determinar a duração das fases larval e de pupa, e a emergência dos adultos em cada temperatura. As relações entre essas variáveis e a temperatura foram analisadas através de ANOVA, regressão e correlação. A temperatura teve grande influência no desenvolvimento das fases imaturas e na emergência dos adultos de H. grandella. A duração do ciclo biológico (ovo-adulto) variou de 30 dias (30ºC) a 104 dias (15ºC). A mortalidade do estágio larval foi alta nessas temperaturas, alcançando taxas de 90% (15°C) e 45% (30ºC). A mortalidade de larvas de primeiro instar foi também relativamente alta (51-75%) nas temperaturas dentro do intervalo de 15ºC a 30ºC, com exceção daquelas que se desenvolveram a 25ºC (14%). O peso das pupas foi menor em temperaturas extremas (15ºC e 30ºC). A estimativa da temperatura base de desenvolvimento para todos os estágios imaturos (8,5ºC) permitiu calcular a constante térmica (1320 graus dias), a qual possibilitará a previsão de picos populacionais no campo. PALAVRAS-CHAVE: Meliaceae, taxa de desenvolvimento, limiar térmico, constante térmica, Costa Rica ABSTRACT -Developmental response of the mahogany shootborer, Hypsipyla grandella (Zeller), to temperature was determined in laboratory trials in Turrialba, Costa Rica. Two hundred fresh eggs (less than 24h old) were placed individually inside glass flasks, and exposed to seven constant temperatures (10, 12.5, 15, 20, 25, 30 and 35°C), in separate experiments. These were carried out in environmental chambers, at 80-90% relative humidity and 8L:16D photoperiod. After hatch, larvae were fed tender foliage of Spanish cedar (Cedrela odorata) and were inspected every 24h to determine larval and pupal duration, and adult emergence, at each temperature. Relationships between these variables and temperature were analyzed by means of ANOVA, regression and correlation procedures. Temperature greatly influenced development of H. grandella immature stages and adult emergence; development time varied between 30 days (30ºC) and 104 days (15°C). Larval mortality was high at those temperatures, reaching values of 90% (15°C) and 45% (30ºC). Also, mortality of the first larval instar was relatively high (51-75%) at all temperatures in the range 15-30°C, except at 25ºC (14%). Pupal weight was lower at extreme temperatures (15ºC and 30ºC). Estimation of a common lower thermal threshold for all immature stages (8.5ºC) allowed calculation of a general thermal constant (1320 degree-days), which could be used to predict population peaks in the field.

A Simplified Low-Cost Diet for Rearing <I>Spodoptera exigua</I> (Lepidoptera: Noctuidae) and Its Effect on <I>S. exigua</I> Nucleopolyhedrovirus Production

“…It mainly damages the new shoots of the red cedar tree (Cedrela odorata L.) (Sapindales: Meliaceae). The larvae feed on the meristematic tissue of these shoots, especially on the apical bud, causing bifurcations in the plant and significantly reducing or annulling the commercial value of infested trees (Newton et al 1993;Taveras et al 2004). There is currently no effective and recommendable method for managing H. grandella populations because the control tactics available often fail to reduce the damage caused by the borer to an economically acceptable level (Newton et al 1993).…”

Development of Swietenia macrophylla King in escape areas

“…Thus, there was no light and space limitations, and, as a result, an absence of competition between individuals. With regard to plant health, the S. macrophylla trees were healthy during the entire period of the study, without records of pests or diseases, even if the study region displays favourable weather conditions for the occurrence of Hypsipyla grandella (TAVERAS et al, 2004).…”

How to Compare the Lower Developmental Thresholds

“…Threshold temperature and effective accumulated temperatures of 10.07° C and 558.36 degree days were reported for the whole generation of green semi-looper, Naranga aenescens, and no obvious differences were observed in their threshold temperatures and effective accumulated temperature between constant temperature studies in the laboratory and alternating temperature studies in paddy fields (Lu et al 2002). The estimated temperature thresholds and thermal constants are useful in the prediction of population peaks (Taveras et al 2004), to identify optimal time of insecticide application (Tolley and Robinson 1986), to estimate intrinsic rate of natural population increase (Kinjo and Arakaki 2002), to develop a forecasting system to monitor the adult emergence and flight activity (Ahmad and Ali 1985), and to develop phenology models (Jarosik et al 2011). The threshold temperatures estimated, particularly T L and T H , are also useful to study the impact of climate change on the distribution of a species (Kocmankova et al 2010).…”