A new species of derelomine weevils (Coleoptera,Curculionidae, Curculioninae: Acalyptini) from the Rovno amber

Protoceletes hirtus sp. nov. (Curculionidae: Curulioninae: Acalyptini) from the Late Eocene Rovno amber is described. This is the second fossil of the genus. The new species is close to P. wolfschwenningerae Rheinheimer, 2007 from Baltic amber and differs it in the separated coxae, asymmetrically convex eyes, longer and clearly semierect hairs on the surface, and the longer body.     

Grandlure dosage and attraction of boll weevils (Coleoptera: Curculionidae)

The effects of grandlure dosage on of boll weevil, Anthonomus grandis grandis Boheman (Coleoptera: Curculionidae), attraction were assessed. Traps collected more boll weevils under field and laboratory conditions as the amount of grandlure in laminated plastic strips was increased from 0 to 10, 30, and 60 mg. Spreading the point source of the lure by cutting the strip into quarters and positioning each quarter on separate corners of the large capacity trap to create an expanded source for the pheromone plume, however, resulted in fewer trap captures than traps with quartered lures all positioned on a single corner. The large capacity trap with the quartered lure on one corner also caught more weevils than the traps with an intact lure fastened to one corner. Although aging lure strips for three weeks reduced emissions of the four pheromone components and their attractiveness to boll weevils, cutting the aged lure into quarters resulted in greater emissions and attraction than lures that were aged intact or as quarters. Some pheromone components volatilized faster than others, resulting in time-related changes in blend ratios, but the underlying factor in boll weevil attraction to grandlure strips was dosage, the amount of volatilized pheromone available for interacting with an adult boll weevil.     

A model for long-distance dispersal of boll weevils (Coleoptera: Curculionidae)

The boll weevil, Anthonomus grandis (Boheman), has been a major insect pest of cotton production in the US, accounting for yield losses and control costs on the order of several billion US dollars since the introduction of the pest in 1892. Boll weevil eradication programs have eliminated reproducing populations in nearly 94%, and progressed toward eradication within the remaining 6%, of cotton production areas. However, the ability of weevils to disperse and reinfest eradicated zones threatens to undermine the previous investment toward eradication of this pest. In this study, the HYSPLIT atmospheric dispersion model was used to simulate daily wind-aided dispersal of weevils from the Lower Rio Grande Valley (LRGV) of southern Texas and northeastern Mexico. Simulated weevil dispersal was compared with weekly capture of weevils in pheromone traps along highway trap lines between the LRGV and the South Texas / Winter Garden zone of the Texas Boll Weevil Eradication Program. A logistic regression model was fit to the probability of capturing at least one weevil in individual pheromone traps relative to specific values of simulated weevil dispersal, which resulted in 60.4% concordance, 21.3% discordance, and 18.3% ties in estimating captures and non-captures. During the first full year of active eradication with widespread insecticide applications in 2006, the dispersal model accurately estimated 71.8%, erroneously estimated 12.5%, and tied 15.7% of capture and non-capture events. Model simulations provide a temporal risk assessment over large areas of weevil reinfestation resulting from dispersal by prevailing winds. Eradication program managers can use the model risk assessment information to effectively schedule and target enhanced trapping, crop scouting, and insecticide applications.     

A study of polyploidy in races of Japanese weevils (Coleoptera: Curculionidae)

The chromosomes of two Japanese weevils, Blosyrus japonicus Sharp and Callirhopalus (= Pseudocneorhinus) obesus Roelofs, were studied. The former consists of four races: one 2n and bisexual (= Blosyrus falcatus Faust) and three parthenogenetic-4n, 5n, and 6n. In general the races are allopatric. The latter species has two races: 4n and 6n, again with distinct geographical distributions.     

Dispersal of boll weevils (Coleoptera: Curculionidae) from cotton modules before ginning

We characterized the level of risk of boll weevil, Anthonomus grandis grandis Boheman, reintroduction to an eradication zone posed by dispersal from cotton modules during and after transport to the gin. Mark-release-recapture experiments in August and September in Texas indicated that most weevils disperse rapidly from the module surface, temperature permitting, unless confined under a module tarp, where most died. Nevertheless, 1-5% of released weevils were recovered alive after 24 h on the side and top surfaces of modules, representing potential dispersants. Mortality of boll weevils caged on the top surface of a module was 95-100% after 1-4 d when maximum air temperatures were > or = 33 degrees C and 72-100% when minimum temperatures were -7 degrees C or lower, but a few survived even after experiencing a minimum daily temperature of -12 degrees C. Under warm (daily maximum temperatures > or = 25 degrees C) and cold (daily minimum temperatures < or = 0 degrees C) weather conditions, survival was higher under the tarp than on the open surface of the module (20 versus 7% and 42 versus 26%, respectively), but mortality was 100% in both locations when temperatures reached 34 degrees C. Our results indicate that although the threat to an eradication zone posed by boll weevil dispersal from an infested module is very low under most environmental conditions, it is probably greatest when 1) a module is constructed and transported from an infested zone during weather too cool for flight, followed by warm weather favorable for flight at the gin yard; or 2) such a module is transported immediately after construction in moderate-to-warm weather.     

Reproductive trade-offs in a specialized plant/pollinator system involving Asplundia uncinata Harling (Cyclanthaceae) and a derelomine flower weevil (Coleoptera: Curculionidae)

The reproductive interactions of a specialized plant/pollinator system involving Asplundia uncinata Harling (Cyclanthaceae) and a derelomine flower weevil (Coleoptera: Curculionidae: Derelomini) were studied at La Selva, Costa Rica. The inflorescences of A. uncinata exhibit a suite of cantharophilous characters including a precisely synchronized anthesis, protogyny, thermogenesis, olfactory attraction of visitors via modified staminodes, and narrow interfloral entrances. The weevil pollinators use the inflorescences for feeding, mating, and oviposition. The larvae are detritivorous and develop either in the detaching staminate flowers or, at a more favorable rate, in the rotting infructescences. The rate of infructescence abortion was high and caused by low levels of pollination. Manual pollination treatments yielded significantly higher seed counts than obtained under natural conditions, and furthermore demonstrated the inflorescences' ability to reproduce via geitonogamy. In the longer term, the reproductive benefits of maintaining low levels of pollination may shift away from the weevils and towards the plants via an increase in the size of the pollinator population.     

Fossil weevils (Coleoptera: Curculionidae) from latitude 85°S Antarctica

Two species of fossil listroderine weevils (Coleoptera: Curculionidae: Rhytirhinini: Listroderina) are reported from the Meyer Desert Formation at a locality on the Beardmore Glacier in the Transantarctic Mountains about 500 km from the South Pole. Associated fossils include wood, leaves and pollen of Nothofagus, stems and leaves of several species of mosses, achenes of Ranunculus, shells of freshwater molluscs and a fish tooth. The age of the fossiliferous strata is contentious but probably within the range of Pliocene to mid-Miocene. The fossils represent organisms that colonised the margins of a glacier at the head of a fjord during an interglaciation. The autecology of the listroderine species indicates that temperatures during summer months averaged 5°C. The mean annual temperature, with winter temperatures constrained by 6 months of darkness, is estimated to have been about −8°C compared to the −26°C estimated for sea level at latitude 85°S today. The closest evolutionary link of the fossil listroderines is with South American rather than Australian or New Zealand taxa. Divergence of the taxa, at least at the level of tribe, had most probably occurred on Gondwana before the continent broke apart. The fossil species are considered to be the descendants of Antarctic lineages which evolved on the continent in the Late Cretaceous or Palaeogene and survived until the Neogene. Extinction of the listroderines and most other Antarctic terrestrial biota occurred with the growth of the polar ice sheets and the change to the polar desert climate.     

New data on the cytology of parthenogenetic weevils (Coleoptera,Curculionidae)

Parthenogenesis and, in particular, polyploidy are rare in animals. A number of cases, known among weevils, represent apomictic parthenogenesis-a reproductive mode in which eggs undergo one maturation division, the chromosomes divide equationally, and no reduction takes place. Among parthenogenetic weevils there are two diploids, 48 triploids, 18 tetraploids, six pentaploids, three hexaploids and one decaploid. Eight examined parthenogenetic species are triploids with 33 chromosomes of different morphology, confirming that triploidy is the most common level of ploidy in weevils. The karyotypes are heterogeneous with the presence of meta-, submeta-, subtelo- and acrocentric chromosomes. The C-banding method showed that only two species possess a large amount of heterochromatin visible as a band around the centromere during mitotic metaphase. This agrees with observations that weevils are characterized by a small amount of heterochromatin, undetectable in metaphase plates after C-banding. In three species an atypical course of apomictic oogenesis occurs with stages similar to meiosis, in which chromosomes form bivalents and multivalent clusters. This association of chromosomes probably represents the remnants of meiosis, although these events have nothing to do with recombination. The results support the hypothesis that the evolution of apomictic parthenogenesis in weevils has proceeded through a stage of automixis.     

New species of sub-fossil weevils (Coleoptera,Curculionidae) in Madagascar copal

Two new species of the subfamily Cossoninae are described from Madagascar copal. Pentarthrum inclusus sp. nov. is similar to P. alpinum Hustache, 1933 but differs in the smaller body size, almost straight rostrum, almost flat eyes, temples with smooth punctures, and the shorter 3rd antennomere. Cossonus shevnini sp. nov. is similar to C. suturalis Boheman, 1838, differing in the unicolorous body, uniformly punctured pronotum, and more convex eyes.     

Captures of boll weevils (Coleoptera: Curculionidae) in traps associated with different habitats

Programs to eradicate the boll weevil, Anthonomus grandis grandis Boheman, from cotton, Gossypium hirsutum L., in the United States rely heavily on pheromone traps for monitoring weevil populations in both active and posteradication maintenance programs. Modifications to trapping protocols that increase trap effectiveness should contribute to this eradication effort. Between October 1996 and May 1997 and between September 1997 and April 1998, we compared trap effectiveness, indicated by the numbers of captured weevils, in relation to selected habitat types. Each study period was divided into fall, winter, and spring seasons. Traps were closely associated with seven habitat types, including four types with prominent erect vegetation (brush-lined irrigation canal, brush, sugarcane, and resaca or ox-bow lake) and three types with only low-growing or sparse erect vegetation (irrigation drainage canal, unimproved pasture, and fallow fields). Captures of male and female weevils were statistically similar regardless of season or trapping habitat. Although captures differed significantly among habitats, these differences varied among seasons. Trapping habitats with prominent vegetational features generally produced higher weekly captures of weevils than habitats lacking these features. Also, captures in traps associated with prominent vegetation indicated seasonal differences in weevil activity, with highest captures occurring during the fall. Traps associated with habitats lacking prominent vegetation did not statistically demonstrate seasonal differences. Our results indicate that immediate trap surroundings strongly influence the effectiveness of the boll weevil pheromone trap. These results also suggest that effectiveness of current trapping programs may be improved through purposeful association of traps with selected vegetational features.     

Formation of the karyosome in developing oocytes of weevils (Coleoptera, Curculionidae)

A complex structure termed the karyosome forms in the nuclei of the developing oocytes of Anthonomus pomorum, Hylobius abietis and Phyllobius sp. (Coleoptera: Curculionidae). It is composed of highly condensed chromosomes, fused with an electron-dense granular material. There are two types of nuclear body associated with the karyosome. The smaller bodies are found in the immediate vicinity of the karyosome. The larger, and more electron-dense, bodies originate next to the condensing chromosomes. During vitellogenesis, the latter bodies disperse in the karyoplasm, and at least some of them locate in the characteristic irregular projections of the germinal vesicle. Morphologically, these projections resemble the accessory nuclei described in other insects. In the studied species, a proteinaceous sheath, the so-called karyosome capsule, surrounds the karyosome. The formation of the karyosome and its capsule occurs during previtellogenesis, so that these structures are fully formed at the onset of vitellogenesis. An extraction of the oocyte cytoplasm with Triton X-100 showed that the material constituting the karyosome capsule is filamentous. Staining with rhodamine-conjugated phalloidin reveals large amount of F-actin in the karyosome capsule.     

Zygotic embryogenesis in Anthurium (Araceae)

Morphological, anatomical, and histochemical aspects of zygotic embryogenesis by Anthurium andraeanum Lind. were investigated from 4 to 24 wk postpollination. Anatomical features were correlated with morphology of the spadix and capacity of embryos to germinate in vitro. Development from a single-cell zygote to fully mature seed takes 24 wk. The suspensor was two ranked and obvious during the early stages of embryogeny. It was apparent by week 8, substantial until week 14, and diminished rapidly until its absence by week 22. Differentiation of the shoot apex, cotyledon, and protoderm occurs at 14 wk. The embryo starts to derive nutrition from the endosperm at this time, and germination of cultured ovules reached 56%. By 20 wk the shoot apex had visible leaf primordia and the root apex was clearly defined. The cotyledon was well developed and surrounded the shoot tip. The storage of protein and starch was at its greatest in the endosperm and embryo. Furthermore, 100% germination of cultured ovules and embryos occurred at 20 wk and thereafter. Fully mature embryos at 24 wk are green and contain protoxylem elements.     

Dispersal of Warren root collar weevils (Coleoptera: Curculionidae) in three types of habitat

Warren root collar weevil, Hylobius warreni Wood, is a native, flightless insect distributed throughout the boreal forest of North America. It is an emerging problem in young plantings of lodgepole pine, Pinus contorta variety latifolia, in western Canada, where larval feeding can kill young trees by girdling the root collar. Susceptible plantings are becoming more abundant following salvage harvesting and replanting activities in the wake of an ongoing epidemic of mountain pine beetle, Dendroctonus ponderosae (Hopkins). Previous studies using mark-trap-recapture methods found that movement rates of adult H. warreni were elevated in areas with high numbers of dead trees, consistent with a hypothesis that the insects immigrate from stands with high mountain pine beetle-caused tree mortality to young plantings in search of live hosts. Sampling methods were necessarily biased to insects captured in traps; however, potentially missing individuals that had died, left the study area, or simply remained stationary. Here, we used harmonic radar to examine weevil movement in three different habitats: open field, forest edge, and within a forest. We were able to reliably monitor all but two of 36 insects initially released, over 96 h (4 d). Weevils released in the open field had the highest rates of movement, followed by weevils released at the forest edge, then weevils released within the forest. Movement declined with decreasing ambient air temperature. Our results suggest that weevils tend to be relatively stationary in areas of live hosts, and hence may concentrate in a suitable area once such habitat is found.     

A study of the chromosomes of thirty-four species of Japanese weevils (Coleoptera:Curculionidae)

The chromosomes of 34 Japanese weevils belonging to 13 subfamilies were investigated in male and/or female germ line cells using squash preparations with the exception of one species studied by sectioning. The results are summarised in Table 1. Excluding two species with Neo-XY, the other 32 species have an Xy_p sex-determining mechanism.

     

A revised study of the chromosomes of twenty-four species of Japanese weevils (Coleoptera: Curculionidae)

The chromosomes of 24 Japanese weevils were reinvestigated in the male germ line using squash preparations. The results are summarized in Table 1. All species have an Xy_p sex-determining mechanism.     

Molecular phylogeny in endemic weevils: revision of the genera of Macaronesian Cryptorhynchinae (Coleoptera: Curculionidae)

A molecular phylogeny and lineage age estimates are presented for the Macaronesian representatives of the weevil subfamily Cryptorhynchinae, using two mitochondrial genes (cytochrome c oxidase subunit 1 and 16S). The Bayesian reconstruction is supplemented by observations on morphology, ecology, and reproductive biology. The present study often corroborates the groups previously outlined in higher‐level informal taxonomies. These and further groups are now assigned new taxonomic status. The following genera and subgenera are described (formerly Acalles): Aeoniacalles gen. nov. , Canariacalles gen. nov. , Ficusacalles gen. nov. , Madeiracalles gen. nov. , Silvacalles gen. nov. (with Tolpiacalles subgen. nov. , Tagasastacalles subgen. nov. ), Sonchiacalles gen. nov. , Echiumacalles gen. nov. (monotypic), Lauriacalles gen. nov. (monotypic), and Pseudodichromacalles gen. nov. (monotypic; formerly Dichromacalles). For the western Palaearctic genus Acalles Schoenherr, 1825 the first subgenus Origoacalles subgen. nov. is described and for the genus Onyxacalles Stüben, 1999 the first subgenus Araneacalles subgen. nov. ; Paratorneuma Roudier 1956 resyn. Except for one species of Acalles (Origoacalles), all of these new higher taxa are endemic to the Macaronesian Islands. All new taxa are presented, together with their host plants and further data, in a synoptic tabular overview. Based on the results of our phylogenetic analysis, we advocate the hypothesis that the evolution of the species in the new genera (of which most group into a ‘Macaronesian clade’) began in the comparatively arid succulent bush zone and that the shady and humid laurel forest of the thermo‐Canarian and thermo‐Madeiran zone was entered much later. Our reconstruction implies that the Canarian and Madeiran archipelagos were colonized by Cryptorhynchinae at least seven times from the continent but saw only one considerable adaptive radiation. It also becomes apparent that it is the ancestor species of the genus Canariacalles– and not Pseudodichromacalles– that features a close connection to the south‐western European and north‐western African species of Dichromacalles s.s. Finally, a key is presented for all genera and subgenera of the Macaronesian Cryptorhynchinae. © 2010 The Linnean Society of London, Zoological Journal of the Linnean Society, 2010, 160 , 40–87.     

Effects of planting dates on boll weevils (Coleoptera: Curculionidae) and cotton fruit in the subtropics

The effects of planting dates 2-3-wk apart on boll weevil, Anthonomus grandis grandis Boheman (Coleoptera: Curculionidae), field-level populations, and feeding and oviposition damage to cotton, Gossypium hirsutum L., squares and bolls, were studied during 2002 and 2003 in the Lower Rio Grande Valley of Texas. Squares were 44-56% more abundant in some later planted treatments than in the earlier planted treatments, but mean cumulative numbers of oviposition- and feeding-damaged squares were 2.7 - 4.8-fold greater in some later planted treatments than in earlier treatments. Increased square production in later planted cotton was offset by boll weevil infestations that occurred when squares are most vulnerable and contribute most toward the pest's reproduction. Early planting avoided boll weevil population buildups in the field when large squares were abundant. Lint yields in 2002 did not differ significantly between the planting date treatments, but in 2003, mean yield in the middle treatment was 23% greater than in the early and late-planted treatments. Insecticide sprays in the earliest planted treatment of each year, based on the 10% damaged squares threshold, were >33% and >43% fewer than in the corresponding middle and latest planting treatments, respectively. Delayed planting, relative to the onset of favorable cotton-growing weather, at the field level, even when not applied uniformly on an areawide scale, is more cost-effective than planting too early or too late.     

New weevils (Curculionidae) in Baltic amber

The new subtribes Palaeorhamphina subtrib. nov. of the tribe Rhamphini and Eocenesibiniina subtrib. nov. of the tribe Tychiini, new genera Archaeoeugnomus gen. nov. (type species A. balticus sp. nov.), Palaeorhamphus gen. nov. (type species P. primitivus sp. nov.), and Eocenesibinia gen. nov. (type species E. prussica sp. nov.), new subgenus Palaeoleiosoma subgen. nov. (type species L. klebsi sp. nov.) of the genus Leiosoma Stephens, and new species Leiosoma klebsi sp. nov., Caulophilus rarus sp. nov., C. squamosus sp. nov., Ceutorhynchus alekseevi sp. nov., C. electrinus sp. nov., Dorytomus nudus sp. nov., Pachytychius eocenicus sp. nov., Archaeoeugnomus balticus sp. nov., Palaeorhamphus primitivus sp. nov., Orchestes tatjanae sp. nov., and Eocenesibinia prussica sp. nov. are described. Electrotribus Hustache, 1942 placem. nov. is transferred from the tribe Derelomini of the subfamily Curculioninae to the tribe Acicnemidini of the subfamily Molytinae. Succinostyphlus erectosquamata (Rheinheimer, 2007) placem. nov. et comb. nov. is transferred from the genus Electrotribus Hustache, 1942 to the genus Succinostyphlus Ku?ka, 1996. These are the first records of representatives of the tribes Plinthini, Acicnemidini, Eugnomini, and Rhamphini in the Baltic amber.     

Potential for transport of boll weevils (Coleoptera: Curculionidae) to the cotton gin within cotton modules

There is concern that cotton gins located in boll weevil, Anthonomus grandis grandis Boheman, eradication zones serving customers in adjacent infested zones may serve as a site for boll weevil reintroductions if weevils are transported alive inside cotton modules. We surveyed fields in three distinct areas of Texas and found that weevils can be present in large numbers in cotton fields that have been defoliated and desiccated in preparation for harvest, both as free adults and as immatures inside unopened bolls. Harvested cotton taken from module builders indicated that approximately = 100-3700 adult boll weevils were packed inside modules constructed at the sampled fields. Marked weevils were forced through a laboratory field cleaner (bur extractor) commonly mounted on stripper-harvesters, and 14% were recovered alive in the seed cotton fraction and lived at least to 24 h. Survival of weevils placed inside modules declined over time up to 7 d, but the magnitude of the decline varied with experimental conditions. In one experiment, 91% of the weevils survived to 7 d, whereas under harsher environmental conditions, only 11% survived that long. Together, our results indicate that when cotton is harvested in an infested area, boll weevils likely will be packed alive into cotton modules, and many will still be alive by the time the module is fed into the gin, at least up to 7 d after the module's construction.