Copyright (c) 2013 University of Nebraska - Lincoln All rights reserved. http://digitalcommons.unl.edu/entomologyother Recent documents in Entomology Papers from Other Sources en-us Thu, 04 Apr 2013 01:39:46 PDT 3600 http://digitalcommons.unl.edu/entomologyother/115 http://digitalcommons.unl.edu/entomologyother/115 Tue, 02 Apr 2013 11:47:23 PDT Book review of The Scarabaeoid Beetles of Nebraska by Brett C. Ratcliffe and Matt J. Paulsen. Bulletin of the University of Nebraska State Museum 22, 2008, 570 p.

]]> Donald B. Thomas http://digitalcommons.unl.edu/entomologyother/114 http://digitalcommons.unl.edu/entomologyother/114 Fri, 22 Oct 2010 12:20:13 PDT The rubber tree is a plant cultivated with the purpose of extraction of the natural rubber (latex), being an important segment of the Brazil economy. Among the main curses that attack the culture, he stands out the tingid, Leptopharsa heveae Drake & Poor (Hemiptera: Tingidae) and among their main natural enemies they stand out the lace wings, the mushroom Sporothrix insectorum and the egg parasitoid Erythmelus tingitiphagus (Soares) (Hymenoptera: Mymaridae). The objective of the work was to report the potential of this natural enemy use, as auxiliary in programs of integrated handling of this pest of rubber plantations. The study was developed in the farm of company "Plantações E. Michelin Ltda.", municipality of Itiquira, Mato Grosso state, Brazil, from October 2005 to February 2006 and from August 2006 to January 2007, being collected ripe folioles of five rubber tree clones (RRIM 600, PR 255, PB 235, PB 217 and GT 1), counted the number of eggs by foliole and the number of emerged parasitoid of the same ones. It was verified an average parasitism rate of 18.8% in the first period and 24.2% in the second.

]]> Rodrigo Souza Santos RSS http://digitalcommons.unl.edu/entomologyother/113 http://digitalcommons.unl.edu/entomologyother/113 Thu, 19 Aug 2010 08:42:24 PDT Planting soybeans [Glycine max (L.) Merrill early and in narrow rows is the most effective cultural control for preventing outbreaks of Helicoverpa zea (Boddie) in soybean. Soybeans planted early in narrow rows close canopy earlier in the season compared with soybeans planted late and in wide rows (i.e., leaves of plants from adjacent rows touch each other and eventually become densely interwoven). Although several lines of research have established dramatically higher mortality for corn earworm eggs or small larvae in closed canopies, none has found the cause. In 1994 and 1995, we planted soybeans in every combination of early (mid-May) and late (mid-June) planting and narrow (0.46 m) and wide (0.92 m) row spacing to provide a spectrum of canopy closure and examined how canopy closure affects populations of foliage-inhabiting predators and their impact on the egg stage of the corn earworm. The most common predators were Nabis spp., Geocoris spp., Orius insidiosus (Say), and spiders. None of these predator groups' abundances was substantially affected by canopy closure. Regardless of canopy closure, predators consumed =70% of H. zea eggs exposed to predation in the field for 24 h in 5 of 6 experiments conducted over 2 yr. Egg predation does not seem to account for differences observed in the survival of this pest between open- and closed-canopy soybean fields.

]]> Aaron C. Anderson et al. http://digitalcommons.unl.edu/entomologyother/112 http://digitalcommons.unl.edu/entomologyother/112 Thu, 19 Aug 2010 08:42:23 PDT Insect populations infesting a small bulk of corn stored in southeastern Georgia were followed for 8 yr by monthly sampling beginning 8 mo after the corn was placed in storage. The species composition of the insect community changed as the corn deteriorated. Nine species became dominant at some stage of succession. Sitotroga cerealella (Olivier) was the dominant species when the first sample was taken. It was succeeded a month later by Oryzaephilus surinamensis (L.), which declined rapidly after 2 mo of dominance and died out during the third year. Cryptolestes ferrugineus (Stephens) was dominant at various times during the first 4 yr. Sitophilus zeamais Motschulsky was dominant during the second year and again briefly during the third. Anisopteromalus calandrae (Howard), a hymenopterous parasite of S. zeamais, was the most abundant species in one sample taken during the third year. Tribolium castaneum (Herbst) was a significant component of the insect community throughout much of the storage period and was the predominant species during much of the third through fifth years. Latheticus oryzae Waterhouse became dominant during the fifth year, after the grain had become heavily damaged and large quantities of frass, flour, and insect remains had accumulated. It remained the most abundant species for 3 yr. Cynaeus angustus (LeConte) became dominant for a brief period during the eighth year and was succeeded by Trogoderma inclusum LeConte, which was the predominant species when the last sample was taken.

]]> R. T. Arbogast et al. http://digitalcommons.unl.edu/entomologyother/111 http://digitalcommons.unl.edu/entomologyother/111 Thu, 19 Aug 2010 08:42:23 PDT Preparation of an artificial oviposition substrate (AOS) from agarose and host hemolymph for oviposition by a parasitic wasp, Microplitis croceipes (Cresson), is described. Natural hosts for this endoparasitoid are larvae of Heliothis spp. Infusion of hemolymph from Heliothis zea (Boddie) into a drop of solidified agar induced females of M. croceipes to oviposit into the material. Ovipositional response to dilution of host hemolymph was determined. The factor or factors that stimulated oviposition were moderately heat sensitive, dialyzable, and unaffected by treatment with protease or pancreatic trypsin or hexane extraction. Hemolymph from Manduca sexta (L.) was less effective than H. zea hemolymph. The AOS will facilitate in vitro efforts to rear M. croceipes, because dissection of host larvae is no longer necessary and many eggs can be collected easily.

]]> R. L. Tilden et al. http://digitalcommons.unl.edu/entomologyother/110 http://digitalcommons.unl.edu/entomologyother/110 Thu, 19 Aug 2010 08:42:22 PDT We studied the biology of Dendroctonus murrayanae Hopkins (Coleoptera: Curculionidae: Scolytinae) in lodgepole pine, Pinus contorta Douglas, in Idaho and Montana. The beetle was not a primary agent of tree mortality. Susceptible host trees were physically damaged, had thin foliage, or were otherwise predisposed to infestation. Beetles attacked individual trees, not in groups, near ground level and at low density. Life stages and their behavior are described. Egg galleries were constructed upward and usually had short spurs. Mating occurred in the egg gallery. Eggs were laid in an elongated group, not in niches, in a shallow excavation along only one side of the egg gallery. Larvae aggregated in a communal chamber, feeding side by side, but separated before pupation. D. murrayanae has four instars. One annual generation is indicated, overwintering as larvae. D. murrayanae occurred in some trees with Pseudips (=Ips) mexicanus (Hopkins), Ips pini (Say), and Hylurgops porosus (LeConte) but seldom with the mountain pine beetle, Dendroctonus ponderosae Hopkins. No natural enemy or commensal insect was observed in brood chambers. A new character on the frons is described and the relationship of D. murrayanae and the spruce beetle, Dendroctonus rufipennis (Kirby), is discussed.

]]> Malcolm M. Furniss et al. http://digitalcommons.unl.edu/entomologyother/109 http://digitalcommons.unl.edu/entomologyother/109 Thu, 19 Aug 2010 08:42:21 PDT The eggs of Lygus hesperus (Knight) were labeled with the element rubidium (Rb) by rearing the nymphs and maintaining the adults on diet with 100, 500, or 1,000 ppm rubidium chloride (RbCl). Anaphes ovijentatus (Crosby and Leonard), a parasite of Lygus spp. eggs, was marked with Rb concentrations above laboratory and field endogenous levels when reared from labeled eggs of Lygus adults fed diets with 500 and 1,000 ppm RbCI. Rb concentrations remained sufficiently high to distinguish labeled parasites from those collected in alfalfa fields for 4 d. The parasites that developed in eggs of L. hesperus reared on diet with 1,000 ppm RbCI tended to be shorter-lived and to produce fewer progeny than those from eggs of Lygus fed diets with lower concentrations, but only differences in longevity of males were statistically significant.

]]> Charles G. Jackson et al. http://digitalcommons.unl.edu/entomologyother/108 http://digitalcommons.unl.edu/entomologyother/108 Thu, 19 Aug 2010 08:42:20 PDT The long-term goal of this study was to use solitary bees to assess the impact of advancing Africanized honey bees (Apis mellifcra scutellata Lepeletier) on the native California bee fauna. Cavity-nesting, solitary bee species were systematically monitored in wooden trap nests at 6 sites in northern central California from 1990 to 1992. Three sites were in the San Joaquin Valley in wildlife refuges or preserves; 3 were in coastal mountain or Sierran foothill parks or reserves. Differences in frequencies of nesting bees were observed and recorded among sites and habitats through time. A Poisson regression indicated that all explanatory variables and their 1st order interactions were highly significant. There were significant differences among bee taxa, sites and years, and their interactions (bee X site; bee X year; site X year). Megachile species were the predominant cavity nesters in the 3 valley sites; Osmia species were the common group in coastal mountain I foothill sites. In a computer simulation, using a variation of the Poisson regression, several significant differences were also observed between yearly frequency counts for certain bee species at the same site. Possible reasons for year to year changes included differential natural mortality, extreme annual weather patterns, use of marginal habitats, and negative impacts from exotic solitary bee species. Three exotic megachilids (Megachile rotundata (F.), M. apicalis Spinola, and M. concinna Smith) have successfully invaded and become established in California. Possibly, M. apicalis has affected other cavity nesting bee species, including the exotic M. rotundata in our Central Valley sites.

]]> Gordon Frankie et al. http://digitalcommons.unl.edu/entomologyother/107 http://digitalcommons.unl.edu/entomologyother/107 Thu, 19 Aug 2010 08:42:20 PDT Augmentative release of the endoparasitoid Cotesia plutellae (Kurdjumov) to control diamondback moth, Plutella xylostella (L.), in cabbage, Brassica oleracea variety capitata (L.), would be expensive for growers if done continually during a growing season. A method for establishing released parasitoids would be very beneficial in the control of this pest. One method under consideration is to use sterile diamondback moth larvae deposited on 'nursery' collard plants as hosts for C. plutellae to allow the parasitoid to build up in numbers and spread into adjacent cabbage fields. Therefore, the ability of C. plutellae to accept and develop successfully in normal and sterile diamondback larvae was evaluated. C. plutellae does not discriminate between normal larvae and larvae from parents sterilized by gamma radiation, and both sets of larvae served as suitable hosts for the parasitoid. Parasitism, foliage consumption, and survivorship were similar for the 2 types of larvae. Adult female Fl parasitoids developed from sterile diamondback larvae were as fit as those from normal larvae. In laboratory bioassays, sterile and normal diamondback larvae traversed similar distances before pupation. Field cage assays showed less distance traversed by both types of larvae compared with the laboratory studies. Survivorship for both types of larvae was very low under field conditions. Results indicate that sterile diamondback moth larvae are acceptable hosts for C. plutellae and suggest that the nursery approach toward establishment and build up of numbers would be a viable approach to in-field production of the parasitoid with little chance for harm to nearby cabbage because of spread of sterile larvae from the nursery plants. This approach could be a cost effective way to augment naturally occurring parasitoids and predators in diamondback moth management programs.

]]> J. S. Okine et al. http://digitalcommons.unl.edu/entomologyother/106 http://digitalcommons.unl.edu/entomologyother/106 Thu, 19 Aug 2010 08:42:19 PDT Extensive published data on the developmental times of nine species of stored-product Coleoptera in relation to temperature, moisture, and diet were described by regression equations. At most temperatures, the order of relative influence of these factors on development was temperature > moisture > diet. However, moisture and diet influenced larval development more than temperature near the optimal temperature for development of each species. Egg, larval, and pupal stage durations at 27°C averaged 15, 66, and 19% of the total developmental time, respectively, at moistures above 12%, and 12, 72, and 15% of total developmental time at moistures below 12%. Similar percentages were found at other temperatures between 20 and 35°C.

]]> David W. Hagstrum et al. http://digitalcommons.unl.edu/entomologyother/105 http://digitalcommons.unl.edu/entomologyother/105 Thu, 19 Aug 2010 08:42:18 PDT Biological assays were used to evaluate the effect of the insect growth regulator fenoxycarb (ethyl (2-p-phenoxyphenoxy) ethyl carbamate) on production of queen-derived dealation inhibitory pheromone and the queen recognition pheromone of Solenopsis invicta Buren. Treated virgin and mated queens weighed less and were less capable of inhibiting dealation by female alates than were nontreated controls. Virgin queens that gained weight during the experimental trials produced more dealation inhibitory pheromone and more queen recognition pheromone than virgin queens that lost weight. Treated virgin queens with fenoxycarb-induced ovary dysfunction inhibited de alation in proportionally fewer alates than treated virgin queens of similar weight that possessed functional ovaries. However, complete ovarian dysfunction in fenoxycarb-treated virgin queens was not associated with reduced quantities of queen recognition pheromone in queen poison sacs. These data support the views that nutritional as well as endocrine factors regulate queen pheromone release and that dissemination of both queen pheromone components is a function of oviposition rate.

]]> Martin S. Obin et al. http://digitalcommons.unl.edu/entomologyother/104 http://digitalcommons.unl.edu/entomologyother/104 Thu, 19 Aug 2010 08:42:17 PDT It is necessary to distinguish new and old gypsy moth, Lymantria dispar (L.), egg masses when conducting gypsy moth population surveys. Egg masses within reach from the ground are touched to determine if they contain unhatched eggs and thus are considered new. The following 2 methods are used for egg masses not within reach: (1) visual discrimination between new and old egg masses or (2) by calculating the percentage of new egg masses at ground level and using this value to adjust counts of all egg masses not within reach. To evaluate these methods, egg-mass persistence and color between generations, the percentage of new and old egg masses at ground level and in the canopy, the ability of observers to visually distinguish new and old egg masses, and the effect of errors on the accuracy of estimates of the percentage of new egg masses was examined. Fifty-five percent of exposed new egg masses studied were still at least 25% intact at the time of the following year's egg-mass survey. However, the color of the egg masses was markedly lighter, providing a mechanism for visually distinguishing new and old egg masses. When egg masses are visually distinguished as new or old with an error rate >0, the resulting estimate of the percent new egg masses is usually biased. The magnitude of the bias varies with the rate of error and the actual percentage of new egg masses in the population, and can result in serious reductions in the accuracy of these estimates. In a field evaluation, new egg masses were incorrectly classified as old 16% of the time and old egg masses were incorrectly classified as new 16% of the time. Because it is unbiased, use of the ratio method to estimate the percentage of new egg masses is recommended whenever 10 or more egg masses are within reach from the ground.

]]> Kevin W. Thorpe http://digitalcommons.unl.edu/entomologyother/103 http://digitalcommons.unl.edu/entomologyother/103 Thu, 19 Aug 2010 08:42:17 PDT We tested natural and factitious host insects for their physiological responses to stinging by the gregarious ectoparasite, Euplectrus plathypenae Howard, and observed hosts injected with tissue from the lower reproductive tract of the female parasitoid. Tests included eight recorded lepidopteran hosts and larvae of 36 other species of Lepidoptera not previously recorded as hosts, plus 19 species in six other orders. The arrestment of development produced by E. plathypenae was expressed in all natural hosts and in most, but not all, insects outside the natural host range of the parasite.

]]> T. A. Coudron et al. http://digitalcommons.unl.edu/entomologyother/102 http://digitalcommons.unl.edu/entomologyother/102 Thu, 19 Aug 2010 08:42:16 PDT Highly erodible lands enrolled in the Conservation Reserve Program soon will revert to agricultural production. This study was designed to determine the effects of reversion of Conservation Reserve Program lands to wheat and livestock production on ground beetle assemblages. Reversion strategies included no reversion of Conservation Reserve Program grass (unmanaged bluestem), simulated grazing of Conservation Reserve Program grass (managed bluestem), minimum- tillage practices for wheat production, and no-tillage practices for wheat production. A randomized block experimental design was established with 4 replicates. More ground beetles were captured in pitfall traps in 1995 than in 1996, and abundances within years differed among reversion strategies. Of the 73 ground beetle species collected, 9 species accounted for 61.7% of total abundance. Abundances of these 9 species differed with respect to reversion strategy. Species diversity and evenness differed among the reversion strategies in 1995, but only evenness differed in 1996. Canonical correspondence analysis showed that annual and monthly variation were the predominant factors in separating ground beetle assemblages. Lack of rainfall may have accounted for a large portion of differences in abundances between years. A partial canonical correspondence analysis showed that simulated grazing and no-tillage wheat were the predominant reversion strategies in separating ground beetle assemblages. These treatments represent disturbance levels intermediate to unmanaged bluestem and minimum-tillage wheat.

]]> B. Wade French et al. http://digitalcommons.unl.edu/entomologyother/100 http://digitalcommons.unl.edu/entomologyother/100 Thu, 19 Aug 2010 08:42:15 PDT Yellow sticky traps are widely used for monitoring and management of whiteflies and certain other pests and have also been used to monitor their natural enemy activity. A new, nonsticky whitefly trap (CC trap), standard yellow sticky cards, and clear colorless sticky cards were evaluated in cotton (Gossypium hirsutum L.) to compare their attractiveness to Eretmocerus eremicus Rose and Zolnerowich, an aphelinid parasitoid of Bemisia argentifolii Bellows & Perring [=Bemisia tabaci (Gennadius) B-strain 1 that is indigenous to southwestern U.S. deserts. The CC traps caught an average of 264 adult whiteflies during 24-h test periods compared with 523 adult whiteflies on yellow sticky traps. The colorless sticky cards trapped only 37 whiteflies per card during the same period. The CC traps caught an average of 0.4 adult E. eremicus over a 24-h period compared with 26.6 adult E. eremicus trapped by yellow sticky cards. Colorless plastic sticky cards trapped an average of 1.1 parasitoids per card, demonstrating that E. eremicus was strongly attracted to the yellow sticky cards. Thirty-nine percent of E. eremicus trapped on yellow sticky cards and 42% trapped on colorless sticky cards were female. CC traps caught the lowest numbers of other arthropods. On average, <1 individual of any other species was captured per CC trap in each 24-h period. Yellow sticky traps caught the greatest number of other arthropods; these included thrips, flies, cotton leafperforator (Buccalatrix thurberiella Busck) moths, small beetles, and other parasitic wasps. Clear sticky traps caught a similar mixture of species but in lower numbers. These results demonstrate that CC traps are highly selective for whitefly, while preserving parasitoid populations. CC traps may be especially useful in greenhouses where yellow sticky traps are frequently used in conjunction with releases of parasitoids.

]]> K. A. Hoelmer et al. http://digitalcommons.unl.edu/entomologyother/101 http://digitalcommons.unl.edu/entomologyother/101 Thu, 19 Aug 2010 08:42:15 PDT Monophyly of a group of four species of Anastrepha is proposed based on characters of the head and the male terminalia. The group includes A. schausi Aldrich; A. Jernandezi Caraballo; A. hermosa Norrbom, n. sp.; and A. bellicauda Norrbom, n. sp. Sexual dimorphism in these species is noted. A discussion of morphological terminology in the Tephritoidea, especially concerning female terminalia, is presented.

]]> Allen L. Norrbom et al. http://digitalcommons.unl.edu/entomologyother/99 http://digitalcommons.unl.edu/entomologyother/99 Thu, 19 Aug 2010 08:42:14 PDT Isozyme studies revealed the existence of an autosomal, male-limited esterase locus (Est-m) in species of the virgifera group of Diabrotica found in the United States. The locus is characterized by the presence of active and null alleles, and particular taxa are monomorphic or polymorphic for the presumptive Est-m variants. Investigations of the properties of an Est-m form present in the western corn rootworm, Diabrotica virgifera virgifera LeConte, produced data to indicate that the enzyme is a carboxylesterase and a glycoprotein with a relative molecular weight of 78,000 ± 8,680 SD. Additional work has shown that Est-m activity is localized in the accessory glands of virgin, adult males 12-14 d old. Moreover, the enzyme is passed to females during mating. The molecular properties of Est-m, its sex-limited expression in the accessory glands of males, and its subsequent occurrence in mated females suggest strongly that it functions in some way in reproduction.

]]> Susan K. Ruud et al. http://digitalcommons.unl.edu/entomologyother/98 http://digitalcommons.unl.edu/entomologyother/98 Thu, 19 Aug 2010 08:42:13 PDT Sterile backcross (Be) males originate from the hybridization of Heliothis subflexa (Guennee) females to H. virescens (F.) males followed by recurrent backcrossing of the fertile female progeny to H. virescens males. Ultrastructural transmission electron microscope (TEM) studies of the postmeiotic maturation of eupyrene sperm cells in Be males, and comparisons with the cells in normal H. virescens males, show that the early stages in cell differentiation and maturation are similar in Be and normal H. virescens males. In 3- or 5-d-old pupae, some of the Be spermatids contain large vacuoles in the cytoplasm or in the mitochondrial derivatives (MDs). Also, the MDs are greatly enlarged at certain levels in the sperm tail and appear normal in other sections. Other structures in the maturing sperm cell, such as the axial filament, cell membranes, manchette system, satellite bodies, and cristae, maintain normal morphology. In more mature eupyrene sperm bundles, it appears that cell membranes often rupture and some of the cells fuse to form abnormal structures with multiple axial filaments and malformed MDs. In any given section we commonly observe some cells with gross abnormalities of the MDs and neighboring cells in the section that are normal. As maturation of the eupyrene sperm bundle continues, the abnormalities become much more severe. In adult Be males, some cells appear normal in some sections. However, in other sections it is difficult to recognize any normal eupyrene sperm cells, and there is generalized breakdown of many cells in the sperm bundle.

]]> Leo E. LaChance et al. http://digitalcommons.unl.edu/entomologyother/97 http://digitalcommons.unl.edu/entomologyother/97 Thu, 19 Aug 2010 08:42:13 PDT We have examined the ultrastructure of post meiotic eupyrene sperm maturation in testes of prepupae, pupae, and adult Heliothis virescens (F.) males. Emphasis was placed on the structures present in the elongating sperm tail. In each young spermatid, each cell has a nucleus, acrosome derivative, and numerous mitochondria in a large volume of cytoplasm. These mitochondria coalesce to form a body, the nebenkern. As the sperm cell begins to elongate, the nebenkern divides into two mitochondrial derivatives (MDs) of unequal size. The MDs have an outer and inner membrane, and as they elongate and coil in the sperm tail, cristae develop on the inner membrane. Concurrent with cell elongation is the disappearance of most of the cytoplasm present in the cell. The axial filament has a typical insect system of 9 + 9 + 2 tubules and is present along most of the length of the sperm tail as are the MDs. A prominent system of tubules, the manchette, forms around the MDs in a later stage of development. Two extracellular structures, the satellite body and the radial mantle, also undergo a complex series of changes during the maturation of the sperm cell.

]]> Leo E. Lachance et al. http://digitalcommons.unl.edu/entomologyother/96 http://digitalcommons.unl.edu/entomologyother/96 Thu, 19 Aug 2010 08:42:12 PDT The organization of the tympanic nerve within the thoracic ganglia of Heliothis zea (Boddie) was investigated. Cobalt chloride infiltration of cut axons was used to investigate the central terminations of the tympanic nerves. The axonal terminals of the A2 acoustic cell were confined to the meso-metathoracic ganglia, whereas the Al acoustic and the nonacoustic B cell were found in the thoracic ganglia. The relevance of this organization for neural circuitry of evasive flight behavior to acoustic stimulation is discussed.

]]> H. R. Agee et al.