A revision of the African species of Oxycarenus (Hemiptera: Lygaeidae)

Abstract

The thesis contains uniform redescriptions of 36 African species of Oxycarenus including 15 species described as new. Figures are presented of each species in a way as to facilitate easy recognition; particular emphasis has been placed on the male genitalia, since they appear to provide significant taxonomic features.Earlier workers based the identification of the members of this group entirely on the colour pattern. In the present work coloration was also found to be indispensable especially in the closely related species, where attention is drawn to the fine and subtle colour differences. However, the use of colour pattern is supplemented by other morphological characters.The importance of the male genitalia as a major taxonomic character is revealed. The study has also indicated that the genus Oxycarenus seems to include three separable groups each apparently deserving subgeneric rank. The recognition characters of these subgenera, as well as keys to them and to the species within each subgenus are given.The study also involved a genetic investigation on one polymorphic new species, Oxycarenus multiformis, whose colour forms were previously confused with other species. Holotypes were examined whenever possible; in cases where these are known to have been lost or destroyed neotypes have been designated.Body measurements were made on dried pinned specimens using a binocular microscope with a micrometer eyepiece. Whenever material was available, five specimens of each sex were measured. With some species sets of measurements were made on individuals from different localities. The lengths of the head, pronotum and scutellum were determined dorsally along the median line.The width of head was taken across the compound eyes including their diameter,The width of pronotum was that of its broadest part.All drawings were made to scale, using a square graticule fitted into the eyepiece of a stereoscopic binocular microscope, from dried pinned specimens. Those of the genitalia and other parts separately illustrated, were made from dissected, unmounted parts of the body held in a cavity slide The detailed studies of the genitalia were initially based on a study of freshly killed material. Copulating pairs were instantly killed in boiling water, the posterior half of their abdomens were detached and treated in warm 10% potassium hydroxide. The sexes were then separated by carefully pulling them apart. However, the majority of the species studied were available only as dried, pinned material. In that case the pygophore was carefully removed from the body and softened in hot water for 10 minutes, then it was transferred to warm 10% potassium hydroxide; the solution was repeatedly changed until muscles had cleared.It was found that the aedeagus could not be satisfactorily inflated by alternate use of 10% potassium hydroxide and distilled water as suggested by Ashlock (1957) and Ahmed (1965). Thus careful dissection by hand was found to be inevitable, although parts of the aedeagus were sometimes damaged.The method ...

Population Fluctuations of Oxycarenus Hyalinipennis and Effect of Certain Compounds on Its Population on Okra in Assiut Governorate

“…hyalinipennis has two generations at okra in Assiut region. In this respect, reproduction and feeding behavior of the genus Oxycarenus were discussed in details by Samy (1969), Dimetry (1971), Hammad et al (1972) and Awan and Qurseshi (1996).…”

Biodiversity of Heteroptera

“…Oxycarenus, by far the largest genus, contains several economically important species (Sweet 2000a), including O. hyalinipennis (Costa) introduced into the New World tropics (Slater and Baranowski 1994). Samy (1969) revised the African fauna and Henry (1997a) gave the group family status.…”

A new host plant of the cotton seed bugs Oxycarenus hyalinipennis (COSTA), in Egypt

“…Oxycarenus hyalinipennis, common name cotton seed bug, is a species of plant bug belonging to the family Lygaeidae, subfamily Oxycareninae (Samy, 1969). The cotton seed bug Oxycarenus hyalinipennis (Costa) is a serious pest of cotton and other malvaceous plants.…”