Environmental conditions influence allometric patterns in the blow fly, Chrysomya albiceps

Change of morphometric and allometric patterns on wings of banded demoiselle (Calopteryx splendens) males in case of ecologically different watercourse types

In the nature, larvae living in watercourses are exposed to a complex system of environmental influences. It is known that different watercourse types (creeks, brooks, streams, little rivers and medial rivers) provide different conditions for larval development (water depth, flow rate, temperature, oxygen content, substrate type, nutrient supply, etc.). These conditions can vary significantly between watercourse types, but be very similar within types. In this work, we examined the body sizes and wing morphometric characteristics of males of Calopteryx splendens reared from different watercourse types (brook, stream, creek, little river, medial river). Although there were no significant differences in body size among watercourse types, we found significant differences in the wing features. We found the most differences between the individuals reared from streams and creeks and between the individuals reared from stream and medial river. Our results show that the individuals reared from different watercourse types were clearly separated on the two wings. The results also suggest that there are significant differences in the number and pattern of allometric features on the wings of individuals reared from different watercourse types.

Landmark Data to Distinguish and Identify Morphologically Close Tabanus spp. (Diptera: Tabanidae)

Tabanus spp., also known as horse flies (Diptera: Tabanidae), are important vectors of several animal pathogens. Adult females of Tabanus megalops and Tabanus striatus, which are members of the T. striatus complex, are morphologically similar and hence difficult to distinguish using morphological characteristics. In addition, molecular identification by DNA barcoding is also unable to distinguish these species. These two species can occur sympatrically with Tabanus rubidus, which is morphologically similar to T. megalops and T. striatus. Wing geometric morphometrics has been widely used in various insects to distinguish morphologically similar species. This study explored the effectiveness of landmark-based geometrics at distinguishing and identifying T. megalops, T. rubidus, and T. striatus in Thailand. Specimens were collected from different geographical regions of Thailand, and only unambiguously identified specimens were used for geometric morphometric analyses. Left wings of females of T. megalops (n = 160), T. rubidus (n = 165), and T. striatus (n = 85) were photographed, and 22 wing landmarks were used for the analysis. Wing shape was able to distinguish among species with high accuracy scores, ranging from 94.38% to 99.39%. We showed that morphologically very close species of Tabanus can be reliably distinguished by the geometry of their wing venation, and we showed how our experimental material could be used as a reference to tentatively identify new field collected specimens.