Mitochondrial COI and morphological specificity of the mealy aphids (Hyalopterus ssp.) collected from different hosts in Europe (Hemiptera, Aphididae)

A New Strain of Lecanicillium uredinophilum Isolated from Tibetan Plateau and Its Insecticidal Activity

A new strain QHLA of Lecanicillium uredinophilum was isolated from a Chinese caterpillar fungus complex and its optimum growth temperature and fermentation conditions were studied. Its insecticidal activity was tested against larvae of seven different insect pests, including Henosepilachna vigintioctopunctata, Spodoptera exigua, Plutella xylostella, Spodoptera frugiperda, Sitobion avenae, Hyalopterus perikonus, and Aphis citricola. The optimum growth temperature was 21–24 °C. The highest spore production of the strain QHLA was 4.08 × 10⁶ spore/mL on solid medium with a nitrogen source of NH₄Cl. However, the highest mycelial growth rate of the strain QHLA was on solid medium with a nitrogen source from yeast extract (4.63 ± 0.03 mm/d). When the liquid medium contained peptone, yeast extract, and glucose, the water content of the mycelia was the lowest, while the spore production was the highest until day 12. When the liquid medium contained glucose, tussah pupa powder, KH₂PO₄, and MgSO₄, the mycelia production was highest until day 8. The bioassay for insecticidal activity indicated that the LC₅₀ values of QHLA were 6.32 × 10³ spore/mL and 6.35 × 10³ spore/mL against Sitobion avenae and Aphis citricola, respectively, while the LC₉₀ values of the strain QHLA against Aphis citricola and Sitobion avenae were 2.11 × 10⁷ spore/mL and 2.36 × 10⁸ spore/mL, respectively. Our results demonstrated that the strain QHLA was a high virulence pathogenic fungus against insect pests, with the potential to be developed as a microbial pesticide.

Las especies de <em>Hyalopterus</em> Koch, 1854 (Hemiptera, Aphididae), pulgones harinosos de los frutales de hueso, en España peninsular e Islas Baleares

Se ha estudiado la distribución de las especies del género Hyalopterus Koch, 1854 (Aphidinae, Aphidini, Rhopalosiphina) en España peninsular e Islas Baleares mediante la revisión de las citas bibliográficas, del material depositado en la colección de la Universidad de León y de las fotografías almacenadas en Insectarium virtual. Se actualiza la distribución de las especies y aportan citas en nuevas provincias. Además, se aporta una clave de identificación para las hembras vivíparas ápteras de las especies de Hyalopterus.

Natural Occurrence of Secondary Bacterial Symbionts in Aphids from Tunisia, with a Focus on Genus Hyalopterus

Aphids (Hemiptera: Aphididae) can harbor two types of bacterial symbionts. In addition to the obligate endosymbiont Buchnera aphidicola Munson, Baumann and Kinsey 1991 (Enterobacteriales: Enterobacteriaceae), several facultative symbiotic bacteria, called secondary (S) symbionts, have been identified among many important pest aphid species. To determine interpopulational diversity of S-symbionts, we carried out a survey in a total of 18 populations of six aphid species collected from six localities in Tunisia, by performing a diagnostic polymerase chain reaction analysis of partial 16S-23S rRNA operon sequences. While 61.7% of individuals contained only Buchnera, three S-symbionts were found at different frequencies. Arsenophonus sp. Gherna et al. 1991 (Enterobacteriales: Enterobacteriaceae) was found in all species under study except for Acyrtosiphon pisum (Harris 1776) (Aphidinae: Macrosiphini); Serratia symbiotica Moran et al. 2005 (Enterobacteriales: Enterobacteriaceae) was present in all analyzed individuals of A. pisum but only sporadically in Aphis spiraecola (Patch 1914) (Aphidinae: Aphidini) and Hyalopterus amygdali (Blanchard 1840) (Aphidinae: Aphidini), while Hamiltonella defensa Moran et al. 2005 (Enterobacteriales: Enterobacteriaceae) was found in all analyzed individuals of one population of Aphis gossypii (Glover 1877) (Aphidinae: Aphidini) and sporadically in two populations of Hyalopterus. The lysogenic bacteriophage APSE-1 (A. pisum secondary endosymbiont, type 1) was detected in the three populations infected with H. defensa. This bacteriophage has been associated with moderate protection against braconid parasitoids in pea aphids. The high prevalence of Arsenophonus sp. in our samples is in accordance with previous studies indicating that, among gammaproteobacteria, this genus is one of the most widespread insect facultative symbionts.

Mitochondrial COI and morphological evidence for host specificity of the black cherry aphids Myzus cerasi (Fabricius, 1775) collected from different cherry tree species in Europe (Hemiptera, Aphididae)

Partial sequences of the mitochondrial COI gene of forty eight European and two Turkish population samples of Myzus cerasi from different winter hosts (Prunus spp.) were subjected to phylogenetic analyses. The analysed M. cerasi samples emerged as paraphyletic relative to a Myzus borealis sample used as an out-group, and formed two major clades in neighbor joining, maximum parsimony, maximum likelihood and Bayesian inference trees, corresponding to subspecies living specifically on Prunus avium and P. cerasus. Multivariate discriminant analysis (method of canonical variates) was applied to find out if morphological variation of samples correlated with mitochondrial COI and host plant information. Mean scores on the first two canonical variables clustered samples fully in accordance with their COI haplotypes and host plants confirming the existence of two morphologically similar winter host - specific subspecies of M. cerasi in Europe. No single morphological character enabled satisfactory discrimination between apterous viviparous females of the two subspecies. A three-character linear discriminant function enabled 92.37% correct identification of apterous viviparous females of M. cerasi cerasi (n = 118) and 93.64% of M. cerasi pruniavium (n = 110). A key for the morphological identification of the two subspecies is presented and their taxonomic status is discussed.