Leptocoris

Abstract: Soapberry bugs are worldwide seed predators of plants in the family Sapindaceae. Australian sapinds are diverse and widespread, consisting of about 200 native trees and shrubs. This flora also includes two introduced environmental weeds, plus cultivated lychee (Litchi chinensis Sonn.), longan (Dimocarpus longan Lour.) and rambutan (Nephelium lappaceum L.). Accordingly, Australian soapberry bugs may be significant in ecology, conservation and agriculture. Here we provide the first account of their ecology. We find five species of Leptocoris Hahn in Australia, and list sapinds that do and do not serve as reproductive hosts. From museum and field records we map the continental distributions of the insects and primary hosts. Frequency of occupation varies among host species, and the number of hosts varies among the insects. In addition, differences in body size and beak length are related to host use. For example, the long-beaked Leptocoris tagalicus Burmeister is highly polyphagous in eastern rainforests, where it occurs on at least 10 native and non-native hosts. It aggregates on hosts with immature fruit and commences feeding before fruits dehisce. Most of its continental range, however, matches that of a single dryland tree, Atalaya hemiglauca F. Muell., which has comparatively unprotected seeds. The taxon includes a smaller and shorter-beaked form that is closely associated with Atalaya, and appears to be taxonomically distinct. The other widespread soapberry bug is the endemic Leptocoris mitellatus Bergroth. It too is short-beaked, and colonises hosts phenologically later than L. tagalicus, as seeds become more accessible in open capsules. Continentally its distribution is more southerly and corresponds mainly to that of Alectryon oleifolius Desf. Among all host species, the non-native environmental weeds Cardiospermum L. and Koelreuteria Laxm. are most consistently attacked, principally by L. tagalicus. These recent host shifts have biocontrol implications. In contrast, the sapinds planted as fruit crops appear to be less frequently used at present and mainly by the longer-beaked species.

Abstract: Contemporary adaptation of plant feeding insects to introduced hosts provides clear cases of ecologically based population divergence. In most cases the mechanisms permitting rapid differentiation are not well known. Here we study morphological and genetic variation associated with recent shifts by the Australian soapberry bug Leptocoris tagalicus onto two naturalized Neotropical balloon vines, Cardiospermum halicacabum and C.grandiflorum that differ in time since introduction. Our results show that these vines have much larger fruits than the native hosts (Whitewood tree -Atalaya hemiglauca- and Woolly Rambutan -Alectryon tomentosus-) and that bugs living on them have evolved significantly longer beaks and new allometries. Genetic analyses of mitochondrial haplotypes and amplified fragment length polymorphic (AFLP) markers indicate that the lineage of bugs on the annual vine C.halicacabum, the older introduction, is intermediate between the two subspecies of L.tagalicus found on native hosts. Moreover, where the annual vine and Whitewood tree co-occur, the morphology and genomic composition of the bugs are similar to those occurring in allopatry. These results show that hybridization provided the genetic elements underlying the strongly differentiated Halicacabum bugs'. In contrast, the bugs feeding on the recently introduced perennial balloon vine (C.grandiflorum) showed no evidence of admixture, and are genetically indistinguishable from the nearby populations on a native host.

Abstract: CITATION: Foster, J. D., et al. 2019. The potential evolutionary impact of invasive balloon vines on native soapberry bugs in South Africa. NeoBiota, 49:19-35, doi:10.3897/neobiota.49.34245.

Abstract: The spermatogenesis of Leptocoris hcematoloma (family Coreidoe) very closely resembles that of Anasa tristis, as described by Paulmier. During the past few years it has been used extensively here in the course on cytology to demonstrate the behavior of the X-chromosome. As a matter of record, it seems worth while to give a very brief account of the spermatocytic divisions. Furthermore, the material is very fine for the study of tetrad formation, and it is hoped later to publish an account of this process. The material on which these observations were made was collected in November and December, I914, on the plant Cardiospermum halicacabum, the balloon vine which is very common in this vicinity. It may be of interest, however, to know that this is the only plant on which we have found this bug. The testes, which are large yellow pear-shaped bodies located at the base of the third pair of walking legs were dissected out in Ringer's solution and fixed immediately in Bouin's fluid. They were stained with iron haematoxylin and counterstained with eosin and light-green. Other fixing agents were used, but this proved to be the best. The material is excellent for the study of spermatogenesis, as the chromosomes are not numerous, and vary greatly in size. It is possible to follow accurately the courses of the smallest, largest and accessory chromosomes throughout their entire history. The spermatogonial complex of Leptocoris hcematoloma consists of thirteen chromosomes (Figs. I and 2). These vary in size, but can be classified in three groups. The members of two pairs 1Contributions from the Zoological Laboratory of the University of Texas, No. I38. 316