Constant fluctuating asymmetry but not directional asymmetry along the geographic distribution of Drosophila antonietae (Diptera, Drosophilidae)

Abstract

RBE 57 1-6 Revista Brasileira de Entomologia xxx (2015) xxx-xxx w w w . r b e n t o m o l o g i a . c o m a b s t r a c tThe population dynamics of a species tends to change from the core to the periphery of its distribution. Therefore, one could expect peripheral populations to be subject to a higher level of stress than more central populations (the center-periphery hypothesis) and consequently should present a higher level of fluctuating asymmetry. To test these predictions we study asymmetry in wing shape of five populations of Drosophila antonietae collected throughout the distribution of the species using fluctuating asymmetry as a proxy for developmental instability. More specifically, we addressed the following questions: (1) what types of asymmetry occur in populations of D. antonietae? (2) Does the level of fluctuating asymmetry vary among populations? (3) Does peripheral populations have a higher fluctuating asymmetry level than central populations? We used 12 anatomical landmarks to quantify patterns of asymmetry in wing shape in five populations of D. antonietae within the framework of geometric morphometrics. Net asymmetry -a composite measure of directional asymmetry + fluctuating asymmetry -varied significantly among populations. However, once net asymmetry of each population is decomposed into directional asymmetry and fluctuating asymmetry, most of the variation in asymmetry was explained by directional asymmetry alone, suggesting that populations of D. antonietae have the same magnitude of fluctuating asymmetry throughout the geographical distribution of the species. We hypothesize that larval development in rotting cladodes might play an important role in explaining our results. In addition, our study underscores the importance of understanding the interplay between the biology of a species and its geographical patterns of asymmetry.

Effects of Diet Quality and Temperature on Stable Fly (Diptera: Muscidae) Development

“…Stressing factors, including limited nutrition and temperature, can lead to developmental instability which may be reflected by asymmetry of bilateral structures or fluctuating asymmetry [28,29]. Symmetry of the length of the D-M wing cell increased relative to the quality of the diet and decreased relative to temperature indicating that both high temperature and poor diet quality increase developmental stress.…”

Use of morphoj soft package for phenotypic and genotypic variety testing (English oak case study)

“…Поскольку именно ФА считается показателем нестабильности раз-вития, признаки с четкой НА не используются в интег-ральном экологическом мониторинге [23]. Вместе с тем присутствие НА в смеси с ФА и способность направ-ленной асимметрии к наследованию вызывают интерес именно к этому виду асимметрии [12,15,27].…”

“…Известно, что в дис-персионном анализе направленная асимметрия в смеси с ФА дает нежелательный «скос» (bias) в величине ФА. Это обстоятельство не мешает определять величину НА, однако фенотипический эффект флуктуирующей асиммет-рии остается недоступным для определения [12,27].…”

Patterns of mandibular asymmetries in two types of companion rabbits

“…Bilateral asymmetries are found in every living being. The disturbances in symmetry can indicate individual or population‐related developmental stress, or pathological conditions, or might be a signal of a relation between structurally or functionally interacting elements (Costa, Mateus, & Moura, ), so a non‐symmetrical structure is not necessarily dissymmetrical, for example pathological. Like many other skeletal structures, the mandible is generally assumed to be bilaterally symmetrical.…”