Comparisons of body size for native and exotic Hymenoptera established in New Zealand

Abstract

ABSTRACT Body size is a fundamental component of morphology, related to many physiological and ecological traits, and is influenced by a variety of biotic and abiotic factors. Body size may also have a role in influencing the establishment of exotic species. We compared the body size of New Zealand native species, accidentally introduced exotic species, and deliberately introduced species of Hymenoptera. Specimens in the New Zealand Arthropod Collection were used to measure body and forewing length. Linear mixed effects regression models were used to compare the overall body sizes between biostatus groups, and specifically between species within a genus and family. A total of 2231 specimens were measured from 740 species of Hymenoptera, comprising 503 native, 201 exotic, and 36 biocontrol species. There was a strong positive correlation between body length and forewing length (R 2 > 0.97). Overall, the average body size of species did not differ significantly between native and accidentally introduced exotic species, but deliberately introduced biocontrol species were significantly smaller than native species. Exotic species had greater interspecific variation in body size than either native or biocontrol species. There were no significant differences in the body sizes of native and exotic species within the same genus or same family. Levene’s tests revealed there was equal variance between biostatus groups at the genus level but unequal variance at the family level. This study provides a large dataset on a key morphological trait, body size, that can be used to further examine how morphology can be shaped by, and influence, ecological communities, and interactions between species.