Aphid population dynamics and identification in Caripe, Venezuela

1 ilus. 3 tab. 9 ref.Los áfidos son el principal vector de diseminación de virus en plantas, donde causan la degeneración de los cultivos por lo tanto, se hace necesario conocer la dinámica poblacional y las especies de áfidos alados en zonas de actividad agrícola. Se utilizaron trampas amarillas de agua, pintadas con esmalte sintético de color amarillo limón (F65YV29, Kem Lustral Sherwin Williams). La trampa fue colocada a una altura de 40 cm sobre el nivel del suelo. La colecta de áfidos se realizó entre enero de 1988 y diciembre de 1989, en la Estación Experimental Local Caripe, en Monagas, Venezuela, a una altura de 1100 msnm. La temperatura promedio para el período de evaluación fue de 20,3°C y la precipitación promedio acumulada de 1145,6 mm. Se recolectó un total de 684 especímenes y 21 especies para el año 1988 y 1095 especímenes y 29 especies para 1989, siendo la especie más abundante Aphis citricola, con 222 y 824 individuos, respectivamente. Aphids are vectors of plant viruses disqualifying crop grown for seeds and consumption. In order to avoid virus incidence it is necessary to know the species present and their dynamics in areas of agricultural activity. Yellow water traps (painted Lemon Yellow F65YV29 Kem Lustral Sherwin Williams), were used in the evaluation. The traps were located 40 cm above ground. The evaluation period ranged from January to December 1988 and 1989, in Caripe, state of Monagas (1100 m above sea level). In 1988, 684 specimens and 21 species were collected, and 1095 specimens and 29 species in 1989. The most common winged species present was Aphis citricola, with 222 and 824 specimens, respectively

First data about the preimaginal morphology of Austroscaeva occidentalis

Preimaginal morphology of Austroscaeva occidentalis (Shannon, 1927) is described for the first time, and the morphology of larvae and pupae of Dioprosopa clavata (Fabricius, 1794) is updated based on material obtained from captive rearing of wild females from Argentina and Venezuela, respectively. We describe the morphology of the third instar larva, head skeleton and puparium using optical microscopy, cryo-scanning and scanning electron microscope. The immature stages of both New World flower fly species are analysed and compared with the known preimaginal morphology of other taxa that belong to the evolutionary lineage of Eupeodes-Scaeva, where Austroscaeva Láska, Mazánek & Mengual, 2018, and Dioprosopa Hull, 1949, form a Neotropical radiation within, together with the genus Notosyrphus Vockeroth, 1969. Larvae of all members of this lineage have abdominal segments 5 and 6 with the tips of the locomotory prominences facing posteriorly, and the anal segment with a characteristic U-shaped grasping organ. Two other larval synapomorphies of this group of genera are the presence of metathoracic setae accompanying ventral sensilla, and the abdominal segments 1–7 with an extra lobe on each locomotory prominence. These two last characters cannot be assessed for Macrosyrphus Matsumura, 1917, and Lapposyrphus Dušek & Láska, 1967, based on published information on larval descriptions. Despite a similar colouration pattern of the fully grown larvae, larval morphology of A. occidentalis and D. clavata are quite distinct. The preimaginal morphology of A. occidentalis has a mixture of morphological characters from the taxa Scaeva Fabricius, 1805, Semiscaeva Kuznetzov, 1985, and Dioprosopa. The larvae of D. clavata show several unique diagnostic features, such as the presence of a slightly serrate outline due to the great development of the segmental spines and a pinnate ornamentation of the setae of its dorsal and dorsolateral sensilla. Regarding their biological cycle, the length of the preadult stages of A. occidentalis is almost 5 days longer than the length observed for D. clavata. In addition, new DNA barcodes are provided for A. occidentalis.Financial support was provided by the programme ‘Doctorar en el extranjero’ of the National University of Cuyo, Mendoza, Argentina