Some Biological Attributes of Sawflies in the Neodiprion fulviceps Complex in a Brushfield Pine Plantation (Hymenoptera: Diprionidae)

Abstract

AbstractAlthough adults from each of four study areas in California showed no morphological differences and were identified as belonging to the Neodiprion fulviceps complex, a number of biological differences in different stages of development indicate that there are three distinct populations of one species or subspecies of a species in the, N. fulviceps complex in California.The life stages are typical of Neodiprion species. Overwintering as eggs, eclosion commences in the spring. The larvae drop to the ground after four to six feeding instars, spinning their cocoons in the duff beneath the host trees. Pre pupal larvae spend the summer in the cocoon; pupation occurs in the fall and adult emergence follows two to three weeks after.The foliage chosen for oviposition is mainly the current year's growth. Oviposition occurs largely in the upper crown of trees less than 10 feet in height, while in trees larger than 10 feet the lower crown is preferred. The outer two-thirds of the foliage of an individual tip and the lower gravitation edges of needles are favored for oviposition.Some of the differences supporting the belief that there are distinct species or subspecies include number of eggs per female, number of needles in each fascicle used for oviposition, number of eggs inserted in each needle, spacing of egg pockets, egg color, number of feeding instars, date of larval eclosion, larval size, and larval feeding capacity.Males and females emerged in synchrony in the laboratory and the field. Males predominated in cocoon collections but females predominated in rearings of larvae. This discrepancy in sex ratio may be due to a differential mortality factor. (In this study no prepupae were found to go into an extended diapause.)One adult morphological character was found that may be of significance in supporting the contention that distinct populations or subspecies occur. Females in one study area generally had more antennal segments than females in other areas. This character along with the biological differences may prove adequate to describe these populations as subspecies or even species in the future bur it was felt that additional names, at this time, would only add to the confusion in the genus. Such descriptions should wait until the entire N. fulviceps complex can be considered.