Morphological and Molecular Characterization of Lema bilineata (Germar), a New Alien Invasive Leaf Beetle for Europe, with Notes on the Related Species Lema daturaphila Kogan & Goeden.

Lema bilineata (Germar) is an alien invasive leaf beetle (Coleoptera: Chrysomelidae) first recorded in Europe in the summer of 2017 in the province of Naples (Campania, Italy). It occurs on both cultivated plants (Nicotiana tabacum) and weeds (Salpichroa origanifolia and Datura spp.). Information on morphological characters, color variation and molecular data are deficient for L. bilineata, as is the case for most Lema species. These data could be useful to discriminate between this species and the closely related Lema daturaphila Kogan & Goeden, which has the same potential to become an alien invasive species. In this paper, color variation in adults and the morphology of the aedeagi and spermathecae of the two species are documented and compared, including micrographic images. Additional data on the current distribution of L. bilineata in Campania is also provided. The cytochrome c oxidase I (COI) barcoding region of both Italian and South African specimens of L. bilineata, as well as South African specimens of L. daturaphila, was sequenced. A preliminary phylogenetic tree is provided, based on the sequences available for Lema species.

To divide or not to divide: An alternative behavior for teratocytes in Encarsia pergandiella (Hymenoptera: Aphelinidae).

Encarsia pergandiella (Hymenoptera: Aphelinidae) is an endoparasitoid with an unusual embryonic development compared to most of congeneric species and all other members of the superfamily Chalcidoidea. The developmental background of this wasp is based on an alecithal hydropic egg, with the embryo developing inside an extra-embryonic membrane which dissociates at hatching into special larva-assisting cells, the teratocytes. In E. pergandiella many teratocytes at hatching were multinucleated syncytial cells with no evidence of a cellular membrane separating the nuclei. These teratocytes during larval development produced smaller uninucleated teratocytes, through successive divisions obtained by progressive ingrowth of the plasmatic membrane, accompanied by appearance of degeneration symptoms, such as protrusions and blebs. As a consequence of this divisional process teratocytes showed a size reduction and an increase in number of about four times during the second day of larval development. Only on the third day of larval life teratocytes started to decrease in number, until total disappearance at larval maturation. This behaviour is in striking contrast with all other studied systems in which teratocytes do not divide and progressively decrease in number as the parasitoid larva develops.

Survey on whiteflies and their parasitoids in cassava mosaic pandemic areas of Tanzania using morphological and molecular techniques.

BACKGROUND: Bemisia tabaci (Gennadius) is the vector of cassava mosaic geminiviruses (CMGs) and cassava brown streak viruses (CBSVs) in Africa, which cause devastating yield losses. As a prerequisite to developing biological control methods and enhancing knowledge of the fauna of whitefly parasitoids in sub-Saharan Africa, endemic parasitoids were surveyed in the cassava-growing regions of Tanzania and analysed using both morphological and molecular methods. An attempt was made to corroborate the identification of the parasitoid species on the basis of consideration of their morphology and sequence analyses of three DNA fragments, namely partial cytochrome oxidase I (COI), the D2 expansion segment of the 28S rRNA and the internal transcribed spacer I (ITS1). RESULTS: Eight whitefly species colonising cassava and twelve species of parasitoids were detected. A species in the Encarsia strenua group and a species in the Eretmocerus mundus group were the most common parasitoids. Molecular systematics indicated the occurrence of two new species of Eretmocerus Haldeman parasitising B. tabaci. CONCLUSION: The accurate identification of natural enemies is an essential first step in developing effective biological control solutions for B. tabaci in Tanzania and the wider cassava-growing environments of Africa. The new data provided here represent an important contribution to this goal.

A new embryonic pattern in parasitic wasps: divergence in early development may not be associated with lifestyle.

Comparative embryogenesis of Encarsia formosa and Encarsia pergandiella (Hymenoptera Aphelinidae), two endoparasitoids of whiteflies (Hemiptera Aleyrodidae), revealed two strongly diverging developmental patterns. Indeed, the centrolecithal anhydropic egg of E. formosa developed through a superficial cleavage, as it occurs in Nasonia vitripennis, Apis mellifera, and Drosophila melanogaster. In contrast, the alecithal hydropic egg of E. pergandiella developed through holoblastic cleavage within a specialized extra-embryonic membrane (EEM). Since this developmental pattern evolved independently in several lineages of hymenopteran endoparasitoids, departures from the superficial cleavage mode have been argued to be strongly canalized in response to a shift from ecto- to endoparasitic lifestyle. Coexistence of both developmental patterns in two congeneric species suggests that alterations of early embryonic development may not be correlated with lifestyle. In addition, embryogenesis of E. pergandiella exhibited the following developmental novelties compared to other species possessing a hydropic egg: (i) polar body derivatives early acquired a cytoskeletal boundary prior to any other cellularization event; (ii) cellularization was asynchronous, starting with an early differentiation of a single apical blastomere at the end of the third cleavage; (iii) appearance of cytoskeletal boundaries of embryo blastomeres occurred between the third and fourth cleavages; (iv) the EEM originated through asynchronous participation of three separate lineages of cleavage nuclei, one of which associated with the polar body derivatives in a syncytium. Our results confirm a scenario of high plasticity in the early developmental strategies of hymenopteran endoparasitoids.