The Pollinators of the Malagasy Star Orchids Angraecum sesquipedale,A. sororium and A. compactum and the Evolution of Extremely Long Spurs by Pollinator Shift

The pollination process of the extremely long-spurred orchids Angraecum sesquipedale and A. sororium is described and documented here for the first time. The pollinaria and viscidia load was examined in moths captured in central and south Madagascar. Visits to orchids by hawkmoths were rarely observed in the field and were therefore systematically recorded in large flight tents using a night-vision video technique and flashlight photography. Angraecum sesquipedale in Fort Dauphin is pollinated by Xanthopan morgani praedicta and A. sororium on Mt. Angavokely by Coelonia solani. By combining a deep nectar spur of extraordinary length with a protruding labellum functioning as a landing platform, these orchids overcome the moth's stereotypic swing-hovering flight thus enabling full insertion of the long tongue. Angraecum compactum in Forêt d'Ambohitantely is pollinated by both the shorter and longer-tongued forms of Panogena lingens which never swing-hover but is also exploited by X. morgani and C. solani with wastage of pollinaria. The duration of tongue insertion, nectar exploitation and tongue withdrawal were analyzed: legitimate and illegitimate visitors differ in their time budget and approach to the flower. Nectar volume, nectar level and sugar concentration of A. sesquipedale and A. sororium were compared with the nectar requirements of the pollinating hawkmoths. The evolution of very long spurs in these orchids is likely to have involved a series of pollinator shifts. The orchids adapted to different hawkmoth species with increasingly long tongues which primarily evolved to avoid predator attacks during visits to less specialized flowers. This “pollinator shift” model modifies the classical “coevolutionary race” model. The relevance of the taxon Angraecum bosseri Senghas is questioned.     

武夷山自然保护区天蛾科昆虫多样性的初步研究

通过2002年至2008年的陆续采集和2009年5月至10月定期系统调查采集,获得武夷山自然保护区的天蛾标本共2 103号,它们隶属于5亚科、33属、75种和亚种.该保护区天蛾科昆虫的区系成分以东洋区种类为主,其次是广布种,并且有少量的古北区种类及特有种;天蛾种类和个体数量的高峰期基本集中在6～8月,鹰翅天蛾Ambul...     

The classification, evolution and biology of the Costa Rican species of Cryptophion (Hymenoptera: Ichneumonidae)

The six known Costa Rican species of the campoplegine ichneumonid genus Cryptophion Viereck are described and keyed. The distribution of species throughout Costa Rica is detailed based on data gathered by an intensive Malaise trap survey of the ichneumonids of the country. Five new species are recognized: C. espinozai. C. guillermoi, C. manueli. C. moragai and C. tickelli , and a sixth, C. inaequalipes (Cresson) redescribed. The monophyly of the genus is demonstrated and the phylogeny of the Costa Rican species reconstructed. Host relationships have been established for all species in Costa Rica; they develop as koinobiont endoparasitoids of first to third instar larvae of Sphingidae or Saturniidae. Analysis of the host relationships from a phylogenetic perspective suggested that the genus first evolved using macroglossine sphingid larvae feeding on rubiaceous understorey plants as hosts, and subsequently diversified to utilize sphingine sphingids and ceratocampine saturniids feeding on a variety of food-plants. Most species appear to be monophagous and oligophagy is apparently a derived feature of one sister-species pair, C. espinozai and C. manueli . In Santa Rosa National Park, Costa Rica, only a small proportion of the species of Saturniidae and Sphingidae present are used as hosts by Cryptophion species. No one host species is parasitized by more than one Cryptophion species. No species of Cryptophion is known to parasitize more than one host species feeding on any one plant species. The monophagous species C. inaequalipes is only known to develop in its sphingid host when that host is feeding on one of its two alternative food-plants.     

Activity pattern and thermal biology of a day-flying hawkmoth (Macroglossum stellatarum) under Mediterranean summer conditions

Abstract.

• 1 The daily activity pattern and aspects of the thermal biology are described for the day-flying hawkmoth, Macroglossum stellatarum L. (Lepidoptera: Sphingidae), while foraging at a flowering population of Lavandula latifolia (Labiatae) under the dry-hot summer conditions of a southeastern Spanish locality.
• 2 The average abundance of M.stellatarum remained fairly constant from sunrise to about 17.00 hours (GMT), and a distinct peak occurred in the evening (18.00—20.00 hours).
• 3 Foraging took place over a broad range of microclimatic conditions, as described by air temperature (T_a; range 19-36°C) and solar radiation (IR; range 1–1025 Wm^-2).
• 4 The thoracic temperature (T_th) of insects remained within relatively narrow limits (39–46°C), with the highest values occurring around noon. Variation in T_th mainly reflected differences in T_a between foraging sites and times. T_th was nonlinearly related to T_a, the rate of increase of T_th with T_a decreasing with increasing T_a.
• 5 The unusual tolerance of high T_th exhibited by M.stellatarum, and its enhanced thermoregulatory capacity at high T_a, enable this species to withstand the severe environmental conditions faced during diurnal foraging in the Mediterranean summer.

     

The cladistics and biology of the Callajoppa genus-group (Hymenoptera: Ichneumonidae, Ichneumoninae)

A cladistic analysis is presented for the genera of the former ichneumonine tribe Trogini. The tribe Heresiarchini is paraphyletic with respect to the Trogini, and so maintaining Trogini as a separate tribe is unsatisfactory. Within Heresiarchini, the following changes are made: (a) the subtribes Apatetorina and Heresiarchina are referred to as the Apatetor and Heresiarches genus‐groups, (b) the genera of the paraphyletic subtribe Protichneumonina are treated as incerta sedis within Heresiarchini, and (c) the Trogini are referred to as the Callajoppa genus‐group, with the former subtribe Trogina referred to as the Trogus subgroup. Thirty‐five genera are recognized as valid within the Callajoppa genus‐group. Catadelphops, Catadelphus, Cobunus, and Facydes are transferred to this group; Holojoppa is removed and is incertae sedis within Heresiarchini. Three new synonyms are proposed: Araeoscelis and Cryptopyge are junior synonyms of Macrojoppa, and Neamblyjoppa is a junior synonym of Catadelphops. Trogus latipennis Cresson is transferred to Pedinopelte from Macrojoppa, and Trogus mactator Tosquinet and its related species (T. bicolor Radoszkowski, T. heinrichi Uchida, and T. tricephalus Uchida) are transferred to Holcojoppa. Tricyphus is redefined and a neotype is designated for Tricyphus cuspidiger Kriechbaumer, the type‐species of the genus. Thirteen new genera are described (authorship of all is Wahl & Sime): Charmedia (type‐species: Charmedia chavarriai Wahl & Sime, sp. n.) , Daggoo (type‐species: Daggoo philoctetes Wahl & Sime, sp. n.), Dothenia (type‐species: Dothenia hansoni Wahl & Sime, sp. n.), Humbert (type‐species: Humbert humberti Wahl & Sime, sp. n.), Laderrica (type‐species: Laderrica feenyi Wahl & Sime, sp. n.), Mokajoppa (type‐species: Tricyphus respinozai Ward & Gauld), Metallichneumon (type‐species: Metallichneumon neurospastarchus Wahl & Sime, sp. n.), Myocious (type‐species: Myocious orientalis Wahl & Sime, sp. n.) , Quandrus (type‐species: Trogus pepsoides Smith, transferred from Callajoppa), Queequeg (type‐species: Gathetus flavibasalis Uchida, transferred from Neofacydes), Saranaca (type‐species: Trogus elegans Cresson; includes Trogus apicalis Cresson, Tricyphyus ater Hopper, and Tricyphus floridanus Heinrich), Tashtego (type‐species: Tashtego janzeni Wahl & Sime, sp. n.), and Xanthosomnium (type‐species: Xanthosomnium froesei Wahl & Sime, sp. n.). A key to the genera of the Callajoppa genus‐group is provided. The evolution of biological traits within the Callajoppa genus‐group is discussed with reference to the elucidated phylogeny. The groundplan biology is parasitism of Sphingidae, with oviposition into a host pupa/prepupa. There have been two transitions to butterfly parasitism within the Trogus subgroup: one a transition to Papilionidae (followed by a switch to Nymphalidae at Psilomastax) and the other to Nymphalidae (followed by a switch to Papilionidae within Macrojoppa). ©2002 The Linnean Society of London. Zoological Journal of the Linnean Society, 134 , 1–56.     

Effects of prey quality on social wasps when given a choice of prey

The effect of prey quality on foraging behavior and colony demographics of the social wasp Polistes fuscatus was examined by providing a choice between non‐toxic prey (Manduca sexta caterpillars) and sublethally toxic prey (Junonia coenia caterpillars), and then comparing the performance of these colonies to others given only the non‐toxic prey. In the choice, one of two types of Manduca were used: those fed an artificial diet or those fed plantain (Plantago lanceolata), which contains iridoid glycosides (IGs) that Junonia coenia store but which Manduca does not. Despite the negative correlation between the number of Junonia prey used and number of adult offspring produced, when a surplus of non‐toxic prey was available, the wasps did not completely avoid the toxic prey. However, they were more discriminating when the choice was between Manduca fed an artificial diet and Junonia fed plantain vs. when both prey species had eaten the plantain. Because the wasps had a choice of prey types and had a surplus of prey on about one‐third of the days, the wasps were able to take enough non‐toxic prey to avoid some of the negative consequences of IGs. For example, the total number of wasp offspring per nest was not affected, but mean weight of female offspring per colony was less for colonies given both prey types eating plantain, compared to that for colonies fed only non‐toxic prey, or those given a choice of non‐toxic prey vs. toxic prey. In addition, compared to the control (only non‐toxic prey), the proportion of males produced was less in the treatment that provided a clear contrast between non‐toxic and toxic prey. Why these wasps did not avoid the toxic prey is discussed.     

Ultrastructural and biochemical basis of the digestion of nectar and other nutrients by the moth Erinnyis ello

The midgut epithelium of adult Erinnyis ello L. (Lepidoptera: Sphingidae) forms ramified villus-like folds. The epithelial cells exhibit long microvilli and narrow and sinuous basal channels studded with particles. These morphological features are thought to be involved in the absorption of nutrients present in low concentration in food. Enzymatic assays in E. ello adults showed the presence of amylase in salivary glands, and the occurrence of aminopeptidase, -fructosidase, - and -glucosidase, trehalase and trypsin in the midgut. Calcium differential precipitation of midgut homogenates showed that aminopeptidase and -glucosidase are integral proteins of the microvillar cell membranes, whereas the other enzymes are soluble or partly soluble and partly membrane bound. Detergent-solubilized aminopeptidase (pH optimum 7.5) sediments as a protein with Mr 120000, whereas trehalase (pH optimum 6.5), as a protein with Mr 95000. The activities of amylase (pH optimum 5.5), -glucosidase (pH optimum 5.0) and trypsin (pH optimum 9.5) were not sufficiently high to be further characterized, whereas -fructosidase and membrane-bound -glucosidase were characterized elsewhere. The data suggest that nectar-feeding E. ello adults are able to some extent to digest and absorb starch and proteins, in addition to nectar sugars. Initial digestion is considered to occur in midgut lumen and final digestion on the surface of midgut cells under the action of microvillar enzymes.

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Résumé L'épithélium de l'intestin moyen des adultes de E. ello L; (Lépido., Sphingidae) est replié en villosités. Les cellules épithéliales présentent de longs microvilli et d'étroits canaux sinueux basaux garnis de particules. Ces caractères morphologiques peuvent être interprétés comme impliquant l'absorption d'aliments présents en faible concentration dans la nourriture. Des études enzymatiques ont révélé la présence d'amylase dans les glandes salivaires, et la découverte d'aminopeptidase, de -fructosidase, d'- et -glucosidases, de tréhalase et de trypsine dans l'intestin moyen. La précipitation calcique différentielle d'homogénats de l'intestin moyen a montré que l'aminopeptidase et l'-glucosidase sont des protéines appartenant aux membranes microvillaires cellulaires, tandis que les autres enzymes sont entièrement ou partiellement solubles et partiellement liées aux membranes. L'aminopeptidase solubilisée par un détergent (pH optimum: 7,5) sédimente comme une protéine de Mr 120000, tandis que la tréhalase (pH optimum: 6,5) comme une protéine de Mr 95000. Les activités de l'amylase (pH optimum: 5,5), de la -glucosidase (pH optimum 5,0) et de la trypsine (pH optimum 9,5) n'étaient pas suffisantes pour être caractérisées, tandis que la -fructosidase et l'-glucosidase liée à la membrane ont été caractérisées ailleurs. Les résultats suggèrent que les adultes E. ello consommateurs de nectar sont capables de digérer et d'absorber une certaine quantité d'amidon et de protéines, en plus des sucres du nectar. La digestion doit débuter dans la lumière de l'intestin moyen pour s'achever à la surface des cellules intestinales sous l'action des enzymes des microvilli.

     

Identification of a pheromone blend attractive to Manduca sexta (L.) males in a wind tunnel

Analyses of solvent rinses of the external surfaces of pheromone glands excised from calling female tobacco hornworm moths, Manduca sexta (L.), revealed the presence of the following compounds: (Z)-9-hexadecenal, (Z)-11-hexadecenal, (E)-11-hexadecenal, hexadecanal, (E,Z)-10,12-hexadecadienal, (E,E)-10,12-hexadecadienal, (E,E,Z)-10,12,14-hexadecatrienal, (E,E,E,)-10,12,14-hexadecatrienal, (Z)-11-octadecenal, (Z)-13-octadecenal, octadecanal, and (Z,Z)-11,13-octadecadienal. The two trienals were identified by mass and PMR spectral analyses and by ozonolyses, and their structures were confirmed by synthesis. In a wind tunnel male tobacco hornworm moths exhibit the same behaviors in response to a synthetic blend of all of the components, the gland rinse, or a calling female. Both (E,Z)-10,12-hexadecadienal and (E,E,Z)-10,12,14-hexadecatrienal are required to stimulate males to complete the characteristic behavioral sequence: anemotaxis, approaching and touching the pheromone source, and bending their abdomens in apparent copulatory attempts. The other components of the blend may play more subtle roles.     

Phenology of Plumeria alba and its Herbivores in a Tropical Dry Forest

Understanding phenology in plant populations requires distinction between proximate mechanisms and ultimate (evolutionary) causation. Leaf production and abscission, flower production, and herbivory were monitored for 2 yr in a population of the stem succulent tree, Plumeria alba L. in the Guánica State Forest in southwest Puerto Rico. Dependence of phenological events on abiotic (rainfall and day length) and biotic factors (herbivore abundance/damage) was quantified to discern potential relationships. Leaf flush and flowering were not associated with periods of highest rainfall as might be expected in a dry tropical forest. Rather, these events were highly correlated with day length. We observed that most leaf flush began in March and April, which was several months before the wettest period of the year (August to November). This result is consistent with other studies that show that leaf flush in Plumeria is under photoperiodic control and that the plants initiate growth and reproduction when cloudiness is low and seasonal light availability is greatest. Herbivore damage by caterpillars of the sphinx moth Pseudosphinx tetrio is restricted primarily to the wettest season, consistent with the hypothesis that early leaf flush and reproduction has been selected to avoid herbivory. It is not clear whether photoperiodic control of leaf flush and reproduction serves to maximize seasonal light availability, minimize the impact of herbivores, or both. However, it is clear that peak rainfall is not likely to have been the sole selective factor determining leaf flush and flowering in P. alba .