Plasticidade morfológica, reprodutiva e assimetria flutuante de Myzus persicae (Sulzer) (Hemiptera: Aphididae) sob diferentes temperaturas

Abstract

-Four clones of the aphid Myzus persicae (Sulzer) were used to assess the magnitude of their responses to seven different temperatures (15.0, 17.5, 20.0, 22.5, 25.0, 27.5 and 30.0 o C). A multivariate index of size was obtained using five morphological characteristics simplified by PCA. Among these characteristics, four were measured bilaterally both sides in order to evaluate the fluctuating asymmetry (FA). Fertility was estimated according to the number of nymphs in the reproductive female apparatus. The variability attributed to the environmental and genetic components was estimated using a genetic quantitative model. A large part of the total variability found for size distribution was attributed to differences in temperature (environmental component), but genetic components of variation were also detected. The plastic potential was considered adaptive, since it increases clone survival in unstable environments and allows new habitat exploitation. However, 30 o C temperature did not permit clone development and survival. Lower variability in one morphological character, the rostrum, in comparison with the other traits may be the result of a stabilizing selection, in relation to its adaptive value to obtain food. The aphids presented FA in some of the measured characteristics. However, no linear relation was detected for the levels of FA and temperature values and no general pattern of variability was found. The data corroborate the hypothesis that size is more effectively affected than FA by external influences, and consequently, is a much more efficient indicator of environmental stress.KEY WORDS: Quantitative genetics, green peach aphid, developmental noise RESUMO -Quatro clones do pulgão Myzus persicae (Sulzer) foram utilizados para se avaliar a magnitude de suas respostas plásticas em sete condições de temperatura 15,0; 17,5; 20,0; 22,5; 25,0; 27,5 e 30,0 o C. Um índice multivariado de tamanho foi obtido por ACP, a partir de cinco caracteres morfológicos. Quatro desses caracteres foram medidos bilateralmente para quantificação da Assimetria Flutuante (AF). A fecundidade foi estimada pelo número de ninfas presentes do trato reprodutivo das fêmeas. A variabilidade atribuída aos componentes ambientais e genéticos de variação foi estimada com o auxílio de um modelo de genética quantitativa. A maior parte da variabilidade fenotípica morfológica na população estudada ocorreu como resposta à temperatura (componente ambiental), mas componentes genéticos de variação também foram detectados. Acredita-se que o potencial plástico descrito seja adaptativo, contudo um ambiente a 30 o C não permitiu a sobrevivência. Pequena variabilidade no comprimento do rostro com relação aos demais caracteres pode ter resultado de seleção estabilizadora, considerando seu valor adaptativo para a obtenção de alimento. Os pulgões apresentaram AF em alguns dos caracteres medidos. Entretanto, não foi detectada relação linear dos níveis de AF com valores de temperatura, nem houve um padrão geral de variação para este caráter. Os ...

Developmental instability in a stem-mining sawfly: can fluctuating asymmetry detect plant host stress in a model system?

“…Weight was consistently highly correlated with fecundity of wheat stem sawfly and is a simpler, much less laborious measure to collect and analyze than FA. A similar pattern was reported for Myzus persicae (Sulzer) (Kanegae and Lomônaco 2003), Haematobia irritans L. (Da Silva et al 2004), Musca domestica L. (Lomônaco and Germanos 2001) and sexual traits reviewed by Bjorksten et al (2000). In conclusion, our study documents the failure of FA as an indicator of plant host stress in this model system, identifies adult weight as a satisfactory indicator of this stress and sawfly fitness and finally, adds to the growing body of literature questioning the value of FA as a biomonitor tool in applied ecology studies.…”

“…Numerous studies have tested the use of FA as a biomonitor (see review by Polak 2003) with some supporting the hypothesis (Bennett and Hoffman 1998;Nosil and Reimchen 2001;Liu et al 2005) and others not (Leung and Forbes 1997;Floate and Fox 2000;Breuker and Brakefield 2003;Kanegae and Lomônaco 2003;Stige et al 2006). Thus, FA remains controversial (see series of articles in Journal of Evolutionary Biology, 10:1-76; and see Møller 1997Møller , 1999Clarke 1998;Houle 1998;Palmer 1999;Thornhill et al 1999;Polak 2003).…”

The Size But not the Symmetry of the Wings of Eulaema nigrita Lepeletier (Apidae: Euglossini) is Affected by Human-Disturbed Landscapes in the Brazilian Cerrado Savanna

“…In order to cope with the environmental stressor and continue their development, some physiological triggers may act during the species ontogenetic development, resulting in smaller adult individuals. For instance, in laboratory conditions, stressors (e.g., high temperatures) have proved to cause an increased development of the studied individuals and a smaller final body size when compared to individuals maintained under low stress conditions (Kanegae & Lomônaco 2003, Chang et al 2007. Pinto et al (2012) found that the specimens of Argia tinctipennis Selys living in anthropized areas had smaller wing sizes than those living in preserved sites.…”

Influence of Pollen on the Development of Africanized Bee Colonies (Hymenoptera: Apidae)

“…These results are strengthened by the assertion that, fluctuating asymmetry and size of subjects may reflect the instability development caused by stress, which in this study may be due to the amount of food available (Scheiner et al 1991, Clarke 1995, Nosil & Reimchen 2001, Kanegae & Lomônaco 2003.…”