Sex-specific glands in tephritid fruit flies of the genera Anastrepha, Ceratitis, Dacus and Rhagoletis (Diptera : Tephritidae)

Abstract

The objectives of this work were to systematically examine males and females of tephritid fruit flies from the genera Anastrepha, Ceratitis, Dacus and Rhagoletis for the presence of possible sex pheromone glands, and to determine whether particular glands may be characteristic of certain genera. Flies from the 4 genera were examined from paraffin embedded histological sections. Pleural epidermal glands and sexually dimorphic, enlarged salivary glands were found in males, but not in females, of 7 species of Anastrepha and in 2 species of Ceratitis. Females of these species do not develop the pleural epidermal glands at all, and although they have salivary glands, the glands do not have the large glandular mass of tissue that is found in males. The pleural glands were similar in all the males, and consisted of a single layer of enlarged, columnar epidermal cells in the pleural region of abdominal segments 3, 4 and 5. The salivary glands of males were divided into 4 types based upon structure. Pleural glands and enlarged salivary glands were searched for, but were not found, in 2 species of Rhagoletis and in 3 species of Dacus. Anal glands, opening externally on the last segment, were confirmed in C. capitata, and were found in C. rosa. Anal glands were not found in any of the other species. A diverticulum from the rectum, the rectal pouch or gland, was confirmed in D. dorsalis, D. cucurbitae and D. tryoni as already published, but this gland was not found in species of other genera. Growth of the pleural glands and salivary glands in males of A. ludens, A. fraterculus and C. capitata was described as a function of age of flies.