Evolutionary patterns in biogeography and host plant association: 'taxonomic conservatism' in Lophopidae (Hemiptera, Fulgoromorpha)

Abstract.  The association between the Lophopidae (Hemiptera, Fulgoromorpha) and their host plants was studied within a phylogenetic framework. Host plant use was optimized on Lophopidae phylogeny and the most parsimonious hypothesis is presented. This hypothesis describes the evolution of host plant use by the Lophopidae, and postulates the ancestral plant family used. This scenario is discussed within the biogeographical evolutionary context of the fulgoromorphan families, and is corroborated by information from both insect and host plant fossils. The association of the Lophopidae and their host plants is made by comparing the angiosperms and Lophopidae phylogenies, demonstrating at this level of comparison that the insects show 'taxonomic conservatism' for their host plants.     

The Labeninae (Hymenoptera: Ichneumonidae): a study in phylogenetic reconstruction and evolutionary biology

The internal phylogenetic relationships of the ichneumonid subfamily Labeninae (Hymenoptera) are re‐assessed using 136 characters for 54 species representing all currently known species‐groups. New character sets are used. These include a new form of seta (named the grossulariform setae) which are present on the inner surface of the hind coxa of some females, and the extensive structural modifications of the terminal segments of the female metasoma, which are described and structural homologies established. The monophyly of the Labeninae and of the four component tribes, Groteini, Poecilocryptini, Xenothyrini and Labenini, is demonstrated. The Groteini is shown to be the sister‐group to the Poecilocryptini + (Xenothyrini + Labenini). Monophyletic genera are established, including three new genera: Ozlabium gen. nov. Gauld & Wahl (type‐species 0. arcadium sp. nov.) in the Groteini from Australia; Torquinsha gen. nov. Gauld & Wahl (type‐species Certonotus invictus Porter) in the Labenini from Chile, and Gauldianus gen. nov. Lanfranco (type‐species Gauldianus chilensis sp. nov. Lanfranco) in the Labenini from Chile. Apechoneura is removed from synonymy and re‐instated as a valid genus for a complex of tropical American species. The biogeographic patterns shown by the Labeninae are discussed. Evidence suggests that the group radiated on Gondwanaland after the separation of Africa/India/Madagascar, but prior to the separation of Australia. Species occurring off the southern continental fragments, in North America, are shown to be members of highly derived lineages, a result consistent with the hypothesis that labenines colonized North America recently through Mesoamerica. Patterns of host utilization and mating behaviour are examined for the group. Members of the more derived lineages show progressively more female specializations for attacking hosts deeply concealed in woody substrates. Males in the more specialized lineages are shown to have a wider array of secondary sexual characteristics and genitalic ornamentations than more plesiomorphic taxa.     

Stable carbon isotopes and the metabolism of the terrestrial Devonian organism Spongiophyton

Devonian fossils of Spongiophyton have been identified as a terrestrial evolutionary intermediate between algae and vascular land plants on the basis of their dichotomously branched, tubular morphology, thick cuticles, and the scattered distribution of surface pores. Our understanding of their physiology is, however, severely limited, but may be increased through the use of stable carbon isotope measurements. One such study led to the hypothesis that Spongiophyton carried a carbon isotope (δ¹³C) signature characteristic of lichens ( Jahren et al., 2003 Geology 31 , 99–102). Here, we outline three difficulties with accepting this idea and report independent isotopic measurements of Spongiophyton fossils from Canada and Ghana. Our results show that the isotopic discrimination of analogous tissues of Spongiophyton, extant lichens, liverworts and mosses are statistically indistinguishable. We suggest therefore that claims to have definitively identified lichen metabolism are premature, and cannot be sustained.     

Mating systems in primitive Lepidoptera, with emphasis on the reproductive behaviour of Korscheltellus gracilis (Hepialidae)

Adults of Korscheltellus gracilis (Grote) are crepuscular. Flight is restricted to two 20–40 minute periods each day: the first flight follows sunset during evening twilight, the other precedes dawn. Four to five times as many adults are active during the evening when courtship, mating and oviposition occur. Of these behaviours, only oviposition occurs during the pre-dawn period of activity. Field observations indicate that females release a sex pheromone while fanning their wings. Females usually fly before pairing. There is no obvious female choice or stereotyped courtship behaviour prior to pairing.
In some hepialid genera females attract males, while in others ( Hepialus Fabricius, Phymatopus Wallengren, Sthenopis Packard and Zenophassus Tindale) the calling system is reversed, with males attracting females. Cladistic analysis of the Hepialidae suggests that the plesiomorphic condition for the family is for females to release the long-distance attractant, and that the reversed calling system represents a derived condition restricted to lineages within a single clade.
Available information on the mating systems of other basal lepidopteran lineages and Trichoptera support the hypothesis that ancestral Lepidoptera possessed a female-released, long-range attractant. Support for this position comes from (1) published literature; (2) field observations made by DLW; (3) the apparent absence of male scent structures and recognizable male calling behaviour among the pre-Neolepidoptera; and (4) cases of male antennal elaboration in several basal lepidopteran lineages.     

A change in the breeding season of Rüppell's Griffon Vultures Gyps rueppellii in the Serengeti in response to changes in ungulate populations

Breeding by Rüppell's Griffon Vultures Gyps rueppellii is synchronized but the time of breeding of colonies in the Serengeti region of Tanzania has changed by 5 months over the period between 1969–1970 and 1985. During this interval there have been considerable changes in the ungulate populations within the feeding range of the vultures, resulting in an increase to the food supply available to the birds. It is suggested that this species may have two alternative breeding seasons, the selective value of each depending on the magnitude of the food supply.     

Cladistics of the genera of Mesochorinae (Hymenoptera: Ichneumonidae)

Abstract. A cladistic analysis is presented for the genera of the ichneumonid subfamily Mesochorinae. Nine genera are recognized as valid. Previous work on larval morphology is reviewed and a number of larvae are newly illustrated and discussed. Four new synonyms are proposed: Oncocotta, Piestetron, Plectochorus and Rhaibaspis are all synonymized with Mesochorus , and Stictopisthus is placed back as a synonym of Mesochorus. Four new genera are described: Artherola from South Africa, Chineater from Chile, Thamester from Japan, and Varnado from Morocco. A new key is provided to the mesochorine genera of the world.     

CELLULAR BIOLOGY OF BONE RESORPTION

Past knowledge and the recent developments on the formation, activation and mode of action of osteoclasts, with particular reference to the regulation of each individual step, have been reviewed. The following conclusions of consensus have emerged.
1. The resorption of bone is the result of successive steps that can be regulated individually.
2. Osteoclast progenitors are formed in bone marrow. This is followed by their vascular dissemination and the generation of resting preosteoclasts and osteoclasts in bone.
3. The exact pathways of differentiation of the osteoclast progenators to mature osteoclasts are debatable, but there is clear evidence that stromal cells support osteoclast generation.
4. Osteoclasts are activated following contact with mineralized bone. This appears to be controlled by osteoblasts that expose mineral to osteoclasts and/or release a factor that activates these cells.
5. Activated osteoclasts dissolve the bone mineral and digest the organic matter of bone by the action of agents secreted in the segregated microcompartments underlying their ruffled borders. The mineral is solubilized by protons generated from CO, by carbonic anhydrase and secreted by an ATP-driven vacuolar H⁺-K⁺-ATPase located at the ruffled border. The organic matrix of the bone is removed by acid proteinases, particularly cysteine-proteinases that are secreted together with other lysosomal enzymes in the acid environment of the resorption zone.
6. Osteoclastic bone resorption is directly regulated by a polypeptide hormone, calcitonin (CT), and locally, by ionized calcium (Ca²⁺) generated as a result of osteoclastic bone resorption.
7. There is new evidence that osteoclast activity may also be influenced by the endothelial cells via generation of products including PG, NO and endothelin.