On the selective forces acting in the industrial melanism of Biston and Oligia moths (Lepidoptera: Geometridae and Noctuidae)

Melanic and typical morphs of Biston betularius (L.), Oligia latruncula (D. & S.) and 0. strigilis (L.) made choices between vertical trunks and horizontal branches, sprayed with white and black paints, in a transparent plastic cylinder in natural illumination. The moths settled in exposed positions. In neither Biston nor Oligia did the choice for white/black backgrounds differ between the morphs. Biston moths settle on narrow branches (not on twigs) with the body at right angles to the longitudinal axis of the branch. The Oligias showed an asymmetrical light reaction: one eye is kept in shadow so that they settle as a continuation of an irregularity of the surface, often of a lichen.
In nature, Biston betularius probably rests high up in the canopies, on the under surfaces of horizontal branches. The visual selection acting on the morphs is expected to be less intensive than that measured on tree trunks. The mark-release-recapture results of Kettlewell (1955a, 1956) do not show any qualitative change during the self-determination of the moths but the material is too limited for firm conclusions.
Newly-hatched Biston males take off straight from the trunk where they have expanded their wings but the females may climb higher in the tree. A hypothesis is presented to explain the black-and-white coloration of f. carbonaria : the short-winged moths climbing up the trunks might deter bird predation.     

Revision of the genus Xylomoia Staudinger (Lepidoptera: Noctuidae), with descriptions of two new species

Seven species are included in the genus Xylomoia Staudinger, two of which are new: X. retinax sp.n. from the Novosibirsk area, Western Siberia, and from the Chelyabinsk area, southern Ural Mountains, and X. stangelmaieri sp.n. from Caorle, Venezia Giulia, on the Adriatic coast. A North American species, Chortodes didonea (Smith) comb.n., is removed from the genus. According to a cladistic analysis, the genus Xylomoia comprises one plesiomorphic species group, the chagnoni group, and two apomorphic groups: the graminea and strix groups. The latter are exclusively temperate Palaearctic. Xylomoia chagnoni (Barnes & McDunnough) is the only Nearctic species of the genus, and the loosely related X. apameaoides (Hacker) was recently described from Turkey. In geographical isolation, these two species have retained many ancestral features. In the more central area, the common ancestor of the graminea and strix groups has evolved into at least five species. The locality and rarity of the species of Xylomoia seemingly result from adaptation of the species to moist habitats, the larvae probably bore inside grass stems (the case of X. chagnoni ). What are called lock-and-key mechanisms may lead to the use of non-independent character states in a cladistic analysis; particularly in the case of homoplasy this kind of double-weighting may result in erroneous cladograms. In Xylomoia , deleting female lock-and-keys affected only the number of cladograms produced, whereas omitting the corresponding male characters had profound effects on the cladogram.     

Immune defence,a possible nonvisual selective factor behind the industrial melanism of moths (Lepidoptera)

It is generally believed that industrial melanism in Lepidoptera is mainly caused by differential predation by birds. In polluted areas, melanic individuals are favoured by natural selection because they are better camouflaged than pale moths on lichen‐free and sooty tree trunks. In this article, we show that, in the black arches moth (Lymantria monacha), melanic morphs have a stronger encapsulation response than pale morphs against nylon monofilament implants. This indicates that the melanic and pale morphs differ in the strength of their immune defence. The same chemical precursors and their end product, melanin pigment, are involved in the encapsulation response and in the external coloration. Thus, it seems that there may be two possible, not mutually exclusive, explanations for the frequency changes observed in the industrial melanism of moths. The dominant gene causes an increase in the amount of melanin pigment and its precursors. This increase causes two changes: an intensified immune defence as a form of improved encapsulation ability of foreign objects, and the well‐known protective dark coloration (a case of relational pleiotropy). It seems possible that industrial melanism is a by‐product of selection on the strength of immunity. In the field, these pleiotropic aspects are exceedingly difficult to distinguish from each other, and the factors may even be compensatory. © 2010 The Linnean Society of London, Biological Journal of the Linnean Society, 2010, 99 , 831–838.     

External ultrastructure of sensory organs in the subfamily lrumuinae (Arachnida, Opiliones, Assamiidae)

The external ultrastructure of sensory organs in edaphic reprerentatives of the subfamily Irumuinae is described. The types of receptor are either bristle-shaped or bulbiform. The bristle-shaped receptors occur on the ventral side of the coxae and displace sensory hairs there. The bulbiform ones are distributed over the scute and on proximal joints (femur, trochanter) of legs. These structures are considered as adaptations to the soil environment.     

Evidence for lock-and-key mechanisms in the internal genitalia of the Apamea moths (Lepidoptera, Noctuidae)

Abstract. Fifty of the fifty-six species of the genus Apamea known from North America and three Palaearctic species were analysed for lock-and-key characters in their internal genitalia, mainly in the male vesica and the female bursa copulatrix. There were an average of 4.5 such characters per species, structurally corresponding in the two sexes. Anatomically they form a postcopulatory but prezygotic isolation mechanism. In some closely related species, the internal genitalia are very similar, but these species have a precopulatory isolation mechanism in the presence or absence of male abdominal coremata. Closely related species did not have more lock-and-key characters than unrelated species, which is taken to indicate absence of character displacement. The anatomical distribution of the lock-and-key characters was examined and the organs of eight species are illustrated.
The lock-and-key hypothesis has been abandoned by several earlier authors but mainly on consideration of external genitalia. In Apamea the invariable functional correspondence between sexes in the sperm transferring organs, and the overall species-specifity of characters but non-existence of interspecific differences under a precopulatory mechanism indicate that (a) lock-and-keys are functioning and (b) they act as isolation mechanisms. Alternative hypotheses of genitalic evolution are reviewed.     

The Noctuoidea (Lepidoptera) described by Linnaeus

Linnaeus described 166 nominal species of Noctuoidea, of which 144 (86.7%) are currently used as valid names, 18 are synonyms, one is a homonym and three taxa remain unknown. Seven taxa were described solely from illustrations in contemporary literature. Lectotypes are designated for 139 (87.4%) of the 159 remaining taxa, 122 of them from the Linnaean collection in London, 13 from the Queen Ludovica Ulrica's collection in Uppsala, Sweden, and four from other contemporary collections. Two Linnaean senior synonyms are introduced: Hada plebeja comb. nov. (Linnaeus, 1761) for the current H. nana (Hufnagel, 1766) and Oeonistis altica (Linnaeus, 1768) comb. nov. for Oe. entella (Cramer, 1779). Erebus occiduus (Linnaeus, 1758) syn. nov. is a junior subjective synonym of E. crepuscularis (Linnaeus, 1758); L. marmorides (Cramer, 1775) Stat. rev. should be reinstated for Letis occidua auct. In two species pairs the Linnaean names have been interpreted incorrectly. The lectotype designation of Phalaena prasinana Linnaeus, 1758, by Lempke (1947) is invalid because the specimen is not syntypic. According to the new lectotype, Pseudoips prasinanus (Linnaeus, 1758) comb. nov. replaces P. faganus (Fabricius, 1781), and Bena bicolorana (Fuessly, 1775) comb. nov. is available for the other species. Abrostola triplasia (Linnaeus, 1758) Stat. rev. replaces A. trigemina (Werneburg, 1864), and for the other species A. triparlila (Hufnagel, 1766) should be reinstated. One neotype designation [Eilema complanum (Linnaeus, 1758)], one lectotype designation [Xylena exsolela (Linnaeus, 1758)], and precedence of a junior synonym [Ophideres fullonia (Clerck, 1764)] over its unused senior synonym are to be referred to the ICZN; until their decision the current usage must be followed. The identity of Mesapamea secalis (Linnaeus, 1758) stat. rev. corresponds to current usage, but, under presence of syntypic material, the recent neotype designation by Lempke (1988) will be referred to the ICZN. The revision is mainly based on the discovery that the insect pins and the way specimens are prepared give evidence of the authenticity of the material. Contrary to the views of earlier authors, Linnaeus had his labels with the specific name pinned against the bottom of the drawers by the specimen pin. Because the labels have been moved twice during subsequent curations, their present position is less indicative of the authenticity than has been previously suggested. The origin of the so-called n-labels is discussed.