Summary: Identification and comparative analysis of
accessory gland proteins in Orthoptera
W. Evan Braswell, Jose´ A. Andre´s, Luana S. Maroja, Richard G. Harrison,
Daniel J. Howard, and Willie J. Swanson
Abstract: Accessory reproductive gland proteins (Acps) in Drosophila evolve quickly and appear to play an important
role in ensuring the fertilization success of males. Moreover, Acps are thought to be involved in establishing barriers to
fertilization between closely related species. While accessory glands are known to occur in the males of many insect
groups, the proteins that are passed on to females by males during mating have not been well characterized outside of
Drosophila. To gain a better understanding of these proteins, we characterized ESTs from the accessory glands of two
cricket species, Allonemobius fasciatus and Gryllus firmus. Using an expressed sequence tag (EST) approach, followed by
bioinformatic and evolutionary analyses, we found that many proteins are secreted and, therefore, available for transfer to
the female during mating. Further, we found that most ESTs are novel, showing little sequence similarity between taxa.
Evolutionary analyses suggest that cricket proteins are subject to diversifying selection and indicate that Allonemobius is
much less polymorphic than Gryllus. Despite rapid nucleotide sequence divergence, there appears to be functional conser-
vation of protein classes among Drosophila and cricket taxa.
Key words: Allonemobius, Gryllus, rapid evolution, reproductive isolation, seminal fluid.
Re´sume´ : Les prote´ines des glandes reproductives accessoires chez le genre Drosophila e´voluent rapidement et semblent
jouer un ro^le important dans le succe`s des ma^les en matie`re de fe´condation. De plus, ces prote´ines sont soupc¸onne´es d'une
implication dans l'e´tablissement de barrie`res a` la fe´condation entre espe`ces proches. Tandis que des glandes accessoires
sont pre´sentes chez les ma^les de nombreux groupes d'insectes, les prote´ines transmises des ma^les aux femelles lors de