Anatomical, phenological and genetic aspects of the host-parasite relationship between Andrena vaga (Hymenoptera) and Stylops ater (Strepsiptera)

Stylops ater is an endoparasite of the mining bee Andrena vaga with extreme sexual dimorphism and hypermetamorphosis. Its population structure, parasitization mode, genetic diversity and impact on host morphology were examined in nesting sites in Germany to better understand this highly specialized host–parasite interaction. The shift in host emergence due to stylopization was proven to be especially strong in A. vaga. Around 10% of bees hosted more than 1 Stylops, with at maximum 4. A trend in Stylops' preference for hosts of their own sex and a sex-specific position of extrusion from the host abdomen was found. Invasion of Andrena eggs by Stylops primary larvae was depicted for the first time. Cephalothoraces of female Stylops were smaller in male and pluristylopized hosts, likely due to lower nutrient supply. The genes H3, 18S and cytochrome c oxidase subunit 1 were highly conserved, revealing near-absence of local variation within Stylops. Ovaries of hosts with male Stylops contained poorly developed eggs while those of hosts with female Stylops were devoid of visible eggs, which might be due to a higher protein demand of female Stylops. Male Stylops, which might have a more energy-consuming development, led to a reduction in head width of their hosts. Host masculinization was present in the leaner shape of the metabasitarsus of stylopized females and is interpreted as a by-product of manipulation of the host's endocrine system to shift its emergence. Stylopization intensified tergal hairiness, most strongly in hosts with female Stylops, near the point of parasite extrusion, hinting towards substance-induced host manipulation.

Geographic Variation in Photoperiodic Response for Induction of Pseudopupal Diapause in Epicauta gorhami (Coleoptera: Meloidae)

Geographical variations in the threshold of environmental cues for diapause induction are important in understanding the life history strategy of insects. Larvae of the bean blister beetle, Epicauta gorhami (Coleoptera: Meloidae), feed on grasshopper eggs and undergo hypermetamorphosis. They normally enter diapause as a pseudopupa (fifth instar). However, when the larvae are reared under long-day and high-temperature conditions, they do not enter pseudopupal diapause but pupate directly from the fourth instar. In addition, this insect is known to modify its photoperiodic response for induction of pseudopupal diapause depending on food availability for larvae. In this study, the larval photoperiodic responses for diapause induction were examined for three populations of E. gorhami collected from the northernmost (Morioka, 39.7°N), central (Kazo, 36.1°N), and southernmost (Takanabe, 32.1°N) parts of its distribution range, and the responses were examined under both fully fed and food-deprived (FD) conditions. Diapause incidence decreased in FD larvae for all populations in long-day conditions, and the critical day-lengths for the diapause incidence were calculated as 14.81, 13.97, and 13.99 h in the Morioka, Kazo, and Takanabe populations, respectively. The results indicate the presence of a geographical variation in larval photoperiodic response, in which diapause is induced earlier in higher latitudinal areas. From these results, together with data for developmental threshold temperature and thermal constant, the Morioka and Kazo populations were suggested to have a partial bivoltine life cycle under the conditions of extremely early oviposition season, a sufficient summer temperature, and poor larval food availability.

Systematics and biology of the new genus Macrosaccus with descriptions of two new species (Lepidoptera, Gracillariidae)

The new genus Macrosaccus Davis & De Prins is proposed for three species formerly assigned to the genus Phyllonorycter: Macrosaccus robiniella (Clemens), Macrosaccus morrisella (Fitch), and Macrosaccus uhlerella (Fitch); two new, closely related species: Macrosaccus neomexicanus Davis and Macrosaccus gliricidius Davis, are also proposed. Descriptions of the adults, pupae, larvae, life histories, and distributions are supplemented with photographs, line drawings, and scanning electron micrographs. Larvae of all species are serpentine/blotch leaf miners on various genera of the plant family Fabaceae. The genus is endemic to the New World, with the invasive species Macrosaccus robiniella now widely established in Europe.

Biology and systematics of the New World Phyllocnistis Zeller leafminers of the avocado genus Persea (Lepidoptera, Gracillariidae)

Four New World species of Phyllocnistis Zeller are described from serpentine mines in Persea (Family Lauraceae). Phyllocnistis hyperpersea,new species, mines the upper leaf surfaces of avocado, Persea americana Mill., and red bay, Persea borbonia (L.) Spreng. and ranges over much of the southeastern United States into Central America. Phyllocnistis subpersea,new species, mines the underside and occasionally upper sides of new leaves of Persea borbonia in southeastern United States. Phyllocnistis longipalpa, new species, known only from southern Florida also mines the undersides of new leaves of Persea borbonia. Phyllocnistis perseafolia,new species, mines both leaf surfaces and possibly fruits of Persea americana in Colombia, South America. As in all known species of Phyllocnistis, the early instars are subepidermal sapfeeders in young (not fully hardened) foliage, and the final instar is an extremely specialized, nonfeeding larval form, whose primary function is to spin the silken cocoon, at the mine terminus, prior to pupation. Early stages are illustrated and described for three of the species. The unusual morphology of the pupae, particularly the frontal process of the head, is shown to be one of the most useful morphological sources of diagnostic characters for species identification of Phyllocnistis. COI barcode sequence distances are provided for the four proposed species and a fifth, undescribed species from Costa Rica.