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A new inquiline oak gall wasp species, Saphonecrus yukawai Wachi, Ide & Abe, sp. nov. (Hymenoptera: Cynipidae: Synergini), is described from Japan. Although most inquiline oak gall wasps are associated with cynipid galls on Quercus trees, the adult wasps of S. yukawai emerged from galls induced by the gall midge Ametrodiplosis acutissima (Monzen) (Diptera: Cecidomyiidae) on Quercus (sect. Cerris) acutissima Carruthers. Host shift from cynipid galls to cecidomyiid galls in inquiline oak gall wasps is discussed.
Anopheles lutzii Cruz (Diptera: Culicidae) is redescribed using specimens collected in Pariquera-Açu, Vale do Ribeira, state of Säo Paulo, southeastern Mata Atlântica, Brazil. Specimens of An. lutzii from Vale do Ribeira and two females from Nova Friburgo, Rio de Janeiro, are compared with three syntypes of An. lutzii, deposited in the Instituto Oswaldo Cruz, Rio de Janeiro. Comparisons of external morphology of specimens from the type locality of Anopheles guarani Shannon demonstrate it is a valid species, and that Anopheles niger Theobald is conspecific with Anopheles guarani stat. rev. The adult male, male terminalia, fourth-instar larva, and pupa of An. guarani stat. rev. are described for the first time. Diagnostic characters of the male and female, male terminalia, fourth-instar larva and pupa of An. lutzii and An. guarani stat. rev. are illustrated. An. guarani stat. rev. is herein resurrected from the synonymy with An. lutzii, and Anopheles niger comb. nov. is transferred from the synonymy with An. lutzii to the synonymy of An. guarani stat. rev.
Laricobius osakensis Montgomery and Shiyake sp. nov., collected from Adelges tsugae Annand on hemlock [Tsuga sieboldii Carr. and Tsuga diversifolia (Maxim.) Mast.] in Japan, is described and illustrated. The new species was collected from several localities on Honshu, Shikokou, and Kyushu Islands. The genus has not been reported previously from Japan. Morphological features, a molecular phylogeny, and diagnostic DNA sites are provided to distinguish this new species from previously described species of the genus. Because of plans to release L. osakensis for the biological control of A. tsugae in eastern North America, a key and discussion are provided to differentiate it from the native North American species, Laricobius nigrinus Fender, Laricobius laticollis Fall, and Laricobius rubidus LeConte, and from two previously imported species—Laricobius erichsonii Rosenhauer, which is endemic in Europe, and Laricobius kangdingensis Zilahi-Balogh & Jelinek, which is endemic in China.
Balaustium medicagoense Meyer & Ryke (Acari: Erythraeidae) and Bryobia spp. Koch (Acari: Tetranychidae) are significant emerging pests in Australian grains and pastures. Despite this, there is limited information known on their basic biology, such as species status and reproductive modes, making it difficult to develop effective and sustainable control strategies. The species/strain status of Balaustium and Bryobia mites from southern Australia was examined using a combination of mitochondrial and nuclear DNA sequence data. In addition, the amplified fragment length polymorphism (AFLP) method was used to examine the reproductive mode and genetic diversity of Ba. medicagoense from 16 populations within southern Australia. Results indicate that there is only one species of Balaustium (Ba. medicagoense) and as many as seven species of Bryobia mites currently present in grain crops, pastures and roadsides within southern Australia. The Bryobia species complex consists of four recently described lineages (Bryobia sp. I, Bryobia sp. IV, Bryobia sp. VII, and Bryobia praetiosa Koch) and three additional genetic lineages (Bryobia sp. VIII, Bryobia sp. IX, and Bryobia sp. X) that have not been described previously. Bryobia sp. VIII, B. sp. IX, and B. sp. I seem to be the most abundant species present in Australian broadacre agriculture (i.e., land suitable for farms practicing large-scale crop [agriculture] operations). The AFLP data revealed that Ba. medicagoense reproduces asexually and that genetic diversity was low with only 10 genotypes found. These findings indicate a new complex of pest mites are present within Australian grain crops and pastures and this has implications for their control.
Several species of Ulidiidae (Diptera) are primary pests of maize (Zea mays L.). The ability to distinguish their immature stages would be useful for biological studies where their distributions overlap. Morphology of the immature stages was examined for three Ulidiidae that attack maíze in the southeastern United States: Chaetopsis massyla (Walker), Euxesta eluta Loew, and Euxesta stigmatias Loew. Egg, larval, and pupal characters were measured and described with the aid of light and scanning electron microscopy. Because of considerable overlap in character states, only a few traits in each stage could be used to separate these three species. C. massyla eggs had pores restricted to the posterior end, but the pores were evenly distributed in the two Euxesta species. Eggs of the two Euxesta species could not be differentiated. Larval mouth hooks of C. massyla had a distinct tooth on their ventral surface, whereas this tooth was lacking in E. eluta and E. stigmatias. Fewer oral ridges were observed on C. massyla larvae than on E. eluta or E. stigmatias. Posterior spiracular slits were apparent in E. stigmatias versus obscure in E. eluta larvae. The length and spinule arrangements on creeping welts could be used to separate E. eluta and E. stigmatias larvae. Posterior spiracular plates of C. massyla puparia were trapezoidal versus ovoid in the two Euxesta species. Puparium color varied significantly among the three species.
Visceral leishmaniasis (VL) or kala-azar is transmitted by parasite-infected sandflies. The female sandfly Phlebotomus argentipes Annandale & Brunetti (Diptera: Psychodidae) carries the protozoan parasite Leishmania donovani (Kinetplastida: Trypanosomatidae) in its gut and injects the pathogen along with its saliva into the bloodstream of a human host. This article reports the successful setup of a very productive laboratory insectarium-based P. argentipes colony, by optimizing breeding conditions and choice of laboratory host animal for blood feeding of the female sandflies. The work also suggests that the source of blood feeding is a critical parameter for egg laying and maturation, which are essential for the maintenance of laboratory colonies of such hematophagous insects.
The cactophilic species Drosophila serido Vilela and Sene 1977 and Drosophila antonietae Tidon-Sklorz and Sene 2001 are two closely related species that have partially overlapping distributions in the Florianópolis-SC locality on the southern Brazilian coast. To characterize this contact zone with respect to possible introgression events and the differential use of cacti hosts, we analyzed male individuals that were collected in their natural environment or from the necrotic cacti in which they were reared, by using aedeagus morphology, isocitrate dehydrogenase isozymes, and the mitochondrial gene cytochrome oxidase I as diagnostic markers. Morphological and molecular markers showed a bimodal distribution, although there was some incongruence, suggesting the presence of asymmetric introgression events. These results suggest that gene flow occurred in the past but then ceased, possibly due to reinforcement of prezygotic reproductive isolation. Analysis of individuals reared in necrotic cacti of two sympatric species in this region showed that D. antonietae, but not D. serido, preferentially uses Cereus hildmannianus Mill. as a cactus host, which may represent an important influence on ecological differentiation by affecting the dynamics of these species in this area of sympatry.
Speciation in periodical cicadas (Magicicada Davis) is closely tied to changes in life-cycle length, which presents a paradox because these organisms depend on emergence synchrony for survival. Recently proposed speciation models invoke developmental plasticity as a possible solution: Environmentally triggered “4-yr accelerations” occur in 17-yr cicadas, suggesting that canalization of induced plasticity could change 17-yr populations into temporally isolated 13-yr populations. However, the reverse shift, 13-yr cicadas emerging in 17 yr, has never been documented. We searched 4 yr after the normal emergence of a 13-yr brood (and in a year with no expected periodical cicada emergences anywhere) and found periodical cicadas active at 26 of 92 sites, with examples of all four 13-yr species. At one location, we found evidence of at least 1,724 cicadas per ha emerging. Few males were heard singing at most sites, so these off-schedule cicadas apparently did not survive long in the face of predation. We also found one 13-yr species singing 8 yr late within the range of a different 13-yr brood, suggesting an 8-yr delayed emergence or consecutive generations of 4-yr delayed cicadas. Developmental plasticity in life-cycle length seems to be similar in 13- and 17-yr cicadas—both types possess the ability to switch to the opposite life cycle and to emerge 1 yr early and/or late. The confirmation of a reverse life-cycle switch in 13- cicadas suggests improvements to theories of life-cycle evolution in Magicicada and strengthens the case for developmental plasticity in speciation.
Singhiella simplex (Singh) (Hemiptera: Aleyrodidae) is a newly invasive pest of several species of Ficus plants in the United States. Very little is known about its biology and life history. Here, we studied its development and reproduction at 15, 20, 25, 27, 30, and 35°C. No immatures survived the 35°C treatment. Stage-specific duration times are presented for the other temperatures. Total duration of immature stages varied from 97.1 d at 15°C to 25.2 d at 30°C. Linear functions were used to describe development rates for eggs, instars and pupal stages. Total immature development also was modeled using a nonlinear Briere-1 function: r(T) = aT(T -T0) where r(T) is developmental rate at temperature (T), a = 0.0000146, T0 = 7.3120084 and TL = 45.9512202 (constant, lower developmental threshold, and lethal temperature, respectively). The thermal requirement for development from eggs to pupae was estimated to be 487.8 degree-days. S. simplex reproduction was highest at 27°C, where R0, GRR, T, r, λ, and DT were 23.114 ♀ / ♀, 24.25 ♀/♀, 31.413 d, 0.099 ♀ / ♀ /d, 1.105 ♀ / ♀ /d, and 6.93 d, respectively. The combined effect of temperature and female adult age on daily oviposition rate was modeled using the Enkegaard equation: eggmean = (p + qT) d exp(-wTd), where T is temperature. Parameter estimates were p = -30.21, q = 2.62, and w = 0.034. Duration of female adulthood was 8 d at 15°C, significantly longer than 2.5–4.2 d at the higher temperatures. At 25 and 27°C, lifetime fecundity per female averaged 37.9 and 46.2, respectively.
Understanding foraging behaviors and food preferences of termite colonies is critical to optimizing control strategies. The relationship between the moisture content (MC) of wood blocks and the feeding preference of Coptotermes formosanus Shiraki (Isoptera: Rhinotermitidae) at three ambient temperatures (19, 28, and 35°C) was investigated with multiple-choice as well as no-choice feeding bioassays. In multiple-choice tests, when four wood blocks with initial MC as dry (0–3%), low MC (22–24%), medium MC (70–90%), and high MC (125–150%) were exposed to workers and soldiers, the highest consumption was found in the high MC wood blocks at all three temperatures, although high MC wood consumption at 19°C was significantly lower than that at 28 or 35°C The preference for high MC wood blocks was detectable within the first few hours and continued for the duration of the test. In no-choice tests, the highest wood consumption also was obtained on the high MC wood blocks at all three temperatures. However, in no-choice tests, significant mortality was observed with termites exposed to dry or low MC wood blocks. Termite mortality was found to be higher with higher ambient temperature. Sustained feeding was not observed on wood blocks with ≤24% MC. When wood moisture is low, no free water exists in the cell cavities, which perhaps influenced feeding choices. Temperature played a vital and complementary role for wood consumption at all moisture levels.
Ctenoplematine Ichneumonidae were sampled with Malaise traps, primarily from central Texas, and dissected to explore variation in reproductive tract morphology, egg size, and egg load. A few species representing the subfamilies Xoridinae, Labeninae, Poemeniinae, Ophioninae, Banchinae, and Tryphoninae were examined for comparison. All ctenopelmatines were synovigenic, but egg size and egg load were highly variable among species. Eggs of koinobionts were always smaller than eggs of the idiobiont taxa Labena, Podoschistus, and Xorides, even after adjustment for body size. Egg loads of koinobionts were significantly larger than those of idiobionts. We discuss our findings in the context of the idiobiont/koinobiont dichotomy and associated life-history traits.
Thermoregulation is crucial for honey bee, Apis mellifera L. (Hymenoptera: Apidae), colony survival in temperate regions, but possible interference by parasites is currently unknown. The small hive beetle, Aethina tumida Murray (Coleoptera: Nitidulidae), and the ectoparasitic mite Varroa destructor Anderson & Trueman are honey bee parasites and both overwinter in host colonies. The efficiency of thermoregulation might thus be affected in infested host winter clusters, due to altered worker activity. Here, we show for the first time that parasites can alter honey bee thermoregulation. Moreover, the data suggest that only combined infestations with V. destructor and A. tumida result in higher thermal maxima in the winter clusters, whereas infestations with one parasite alone had no significant effect compared with the controls. Due to the ubiquitous mite V. destructor combined infestations with parasites or combined infections with pathogens are almost inevitable. Therefore, our data indicate that an altered thermoregulation due to multiple infestations might be another widespread factor contributing to winter losses of honey bee colonies.
Wolbachia infections were investigated by sequencing the wsp and ftsZ genes in a population of the endangered butterfly Zizina emelina (de l'Orza) (formerly Zizina otis emelina) (Lepidoptera: Lycaenidae), in Toyonaka City, northern Osaka Prefecture, central Japan. Wolbachia was detected in 65, 77, and 86% of field-collected adults in 2004, 2005, and 2007, respectively. Sequencing results revealed the presence of two strains of Wolbachia, wEmeTnl and wEmeTn2, in adults of this population, although no double infection was found. Three (12.5%) of 24 field-collected females infected by wEmeTnl produced offspring with a female-biased sex ratio, whereas all females infected by wEmeTn2 produced almost all-female offspring. In contrast, no uninfected females produced female-biased offspring. Moreover, the mean egg hatchability of broods from wEmeTn2-infected females was almost half that of uninfected females. These results indicate that at least wEmeTn2 is a male-killing strain.
We investigated how environmental variables influence development and survivorship of Boreioglycaspis melaleucae Moore (Hemiptera: Psyllidae) by quantifying life history characteristics of adults, eggs, and nymphs when held at eight constant temperatures, four relative humidities, and on plants that differed in foliar terpenoid profiles. There is insufficient evidence to conclude that terpenoid profiles or humidity influence B. melaleucae development. Although longevity of adult psyllids is greater on plants that contain E-nerolidol versus viridiflorol profiles, this does not translate to a longer ovipositional period or increased fecundity. Similarly, humidity treatments had a limited and inconsistent effect on B. melaleucae developmental rates and nymphal survivorship. In contrast, developmental rates increased linearly with increasing temperature to an optimum 25°C, whereas greater temperatures caused total developmental rates to decrease. Temperature also affected nymphal survivorship, with no individuals completing development below 10 or above 30°C. Mean maximum daily temperatures in southern Florida commonly exceeded 30°C, with maximum temperatures ranging from 30 to 35°C (in Broward Co.) during 138 d in 2006. Therefore, we conclude that lethal upper temperature thresholds will limit population growth rates during summer.
Feeding attractants for moths are useful as survey tools to assess moth species diversity and for monitoring of the relative abundance of certain pest species. We assessed the relative breadth of attractiveness of two such lures to moths, at sites with varied habitats during 2006. Eighty-six of the 114 species of Lepidoptera captured were in traps baited with acetic acid plus 3-methyl-1-butanol (AAMB), a moth lure that is based on the odor chemistry of fermented molasses baits. Fifty-two of the 114 species were trapped with a floral odorant lure comprised of phenylacetaldehyde, β-myrcene, methyl salicylate, and methyl-2-methoxy benzoate. Preference for one lure type was statistically supported for 10 species of moths: seven to the AAMB lure and three to the floral lure. To gain better information on lure preference, 10 pairs of traps baited with the same lures were maintained in a single habitat type (riparian) during 2008. Sixty-eight of 89 species captured were in traps baited with AAMB, and 43 were in traps baited with the floral lure. Preference for a lure type was statistically supported for 39 of the 89 species of moths trapped; 32 to the AAMB lure and seven to the floral lure. Both of these lures hold advantages for trapping different types of moths, and both lures might be used in a complementary way to sample moth biodiversity.
Lepidopteran stem borers were collected from switchgrass, Panicum virgatum L., tillers showing symptoms of infestation at seven locations in Illinois and Iowa, with additional observations made on larval and adult activity. Blastobasis repartella (Dietz) (Coleophoridae), whose only known host is switchgrass, was common in plots grown for >5 yr, whereas the polyphagous stalk borer, Papaipema nebris (Guenée) (Noctuidae), was abundant in newly established (i.e., first- and second-year) switchgrass. Haimbachia albescens Capps (Crambidae) was collected from two locations in Illinois, making switchgrass the first known host for this species. Entry holes made by B. repartella and H. albescens were usually 1–2 cm above the soil surface, precluding discrimination between these species based on external appearance of damage. Although P. nebris often entered stems within 5 cm of the soil surface, they also seemed to move between stems and were the only species entering stems at heights >15 cm. Adults of B. repartella were active on and above the switchgrass canopy by 2130 hours, with peak activity at ≈0230 hours. Activity of B. repartella adults seemed greatly reduced on one night with relatively cool temperatures and low wind speeds. Data from switchgrass and giant ragweed, Ambrosia trifida L., suggest P. nebris larvae move out of switchgrass during July in search of hosts with larger diameter stems, although by then hosts such as corn, Zea mays L., or Miscanthus spp. may have outgrown the potential for serious damage. However, switchgrass could contribute to greater adult populations of P. nebris if thick-stemmed hosts such as giant ragweed are not managed.
The corn leafhopper, Dalbulus maidis (DeLong & Wolcott) (Hemiptera: Cicadellidae), is a vector of three maize, Zea mays L., pathogens that have become limiting factors for maize production in some areas of the Americas. Insect feeding plays an important role in vector acquisition and inoculation of pathogens and hence the disease spread. Thus, we sought to understand the different probing and stylet penetration activities performed by this insect while feeding on maize plants, with the ultimate goal of characterizing potential sources of insect resistance in maize. Using electrical penetration graph technology, six distinct waveforms were characterized and correlated with major probing activities of D. maidis via transmission of corn stunt spiroplasma and excretion of honeydew as markers. Major waveforms comprise stylet pathway (waveform 1), active ingestion in nonsieve elements (waveform 2), nonvascular probing (waveform 3), phloem contact (waveform 4, the X wave), phloem ingestion (waveform 5), and oviposition (waveform 6). Our results support most previous findings with this species, and also indicate that some waveforms (2, 4, and 5) are related to biopotentials generated during probing, as was previously found for other hemipteran species. The most important finding from this work is that D. maidis ingests from phloem sieve elements more frequently and for longer durations than seen in previous research, probably due to longer observation periods used in this study. This work provides basic information relevant to the understanding of probing behavior of D. maidis and to the characterization of potential sources of insect-resistant maize.
Candidatus Liberibacter asiaticus (CLas) bacterium has been strongly implicated as the causative agent of huanglongbing (HLB), or citrus greening, which is currently the most devastating citrus disease worldwide. HLB is transmitted by the Asian citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Psyllidae), in a persistent manner. We used quantitative-polymerase chain reaction (PCR) to detect CLas in dissected organs of individual D. citri adults infected with HLB in the laboratory or collected from field-infected citrus trees in South Florida. The proportion of infected (CLas-positive) dissected organs was 47–70% for the salivary glands, 72–80% for the alimentary canal, and 79–97.5% for the rest of the insect body. Statistical analysis indicated that, in both field- and laboratory-infected D. citri, the proportion of infected salivary glands was significantly lower than that of other parts in the insect body. With field-collected psyllids, the relative copy number of CLas genomes, compared with psyllid genomic DNA in each sample, was significantly higher in both the salivary gland and alimentary canal compared with that in the rest of the insect body for both males and females. These results provide the first PCR confirmation of CLas in the alimentary canal and salivary glands of D. citri and strongly suggest that the salivary glands constitute an important transmission barrier to CLas in the psyllid vector. Our results also suggest that CLas may replicate or accumulate in both the alimentary canal and salivary glands of D. citri.
North American tiger beetles (Cicindela spp. L.) have been reared in the laboratory for more than a century, and here we summarize the relevant literature to develop a general rearing protocol. We used this protocol to experimentally overwinter adults in the laboratory and observe variation in oviposition and fecundity among several species. Overwintering experiments, involving five North East North American Cicindela species with spring-fall life histories—Cicindela repanda (Dejean), Cicindela hirticollis (Say), Cicindela purpurea (Olivier), Cicindela scutellaris (Say), and Cicindela tranquebarica (Herbst) —demonstrated that both a long cooldown (20 to 4°C by a degree a day) and a short photoperiod (8:16 [L:D] h) maximized survival and minimized overwintering weight loss, which varied between species and sex. Observations of oviposition, larval abundance and larval development involving five Cicindela species with summer life histories revealed that Cicindela punctulata (Olivier) produced more first-instar larvae than Cicindela abdominalis (F.), Cicindela dorsalis dorsalis (Say), Cicindela puritana (Horn), or Cicindela unipunctata (F.) and that high mortality due to accidental desiccation may be overcome by rearing larvae individually in tubes rather than in bins. We also present a first account of larval rearing of the federally threatened species C. puritana and the northern Martha's Vineyard population of the federally threatened species C. d. dorsalis. Notably, C. d. dorsalis produced fewer larvae than more common species reared in this study. We conclude that rearing large numbers of larvae is feasible with endangered as well as common species and we propose future improvements for rearing as part of conservation efforts.
A novel brush-induced method to physically stimulate salivation was applied to the glassy-winged and smoke tree sharpshooters (Hemiptera: Cicadellidae: Cicadellinae). This technique enabled the direct observation of salivary secretion processes, solidification of saliva, and collection of salivary secretions. For both species, brush-induced saliva was first secreted in liquid form, a portion of which gradually solidified to form the salivary sheath for both sharpshooter species. Proteins of similar molecular weight were obtained from brush-induced saliva extracts from both sharpshooters. Extracts from dried sheaths collected from Parafilm membranes over artificial diet had a different protein profile from brush-induced saliva extracts. The latter contained fewer proteins than extracts of the liquid content of salivary glands. Two proteins appeared in all three of the extracts from hemolymph, salivary glands, and brush-induced saliva, one of which also appeared in dried sheath extracts. Our findings support previous research by others that there is a limited flow of protein from hemolymph to salivary glands and brush-induced saliva. There is also some protein modification associated with saliva solidification. The quantity and composition of proteins suggest the brushinduced saliva collection method has merit for future biochemical analyses of saliva. The implications of this work could potentially include illuminating the mechanism of inoculation by the Pierce's disease bacterium, Xylella fastidiosa.
Bark beetles (Coleoptera: Curculionidae: Scolytinae) are economically and ecologically the most important group of forest insects. They use several monoterpenes produced by their host plants to locate and colonize trees. Some of these compounds also are metabolized to produce sex, aggregation, or antiaggregation pheromones. Experimental studies have shown that certain terpenes are highly toxic to the insects, negatively affecting their development, reproductive success, and colonization of host trees. Nevertheless, the effects of these compounds on specific organs or anatomical systems are unknown. Based on relationship between bark beetles and monoterpenes of their host trees and the midgut morphological characterization performed previously, we studied the effects of α-pinene and myrcene on midgut cells of the red turpentine beetle, Dendroctonus Valens LeConte. Our results show that both α-pinene and myrcene induce an increase in the numbers of lysosomes and mitochondria. Outer and inner mitochondrial membranes were very conspicuous but were not disrupted. Both smooth and rough endoplasmic reticula were abundant and were found throughout the cytoplasm. Two kinds of secretory vesicles were observed: one associated with digestive material and the other associated with “flocculent” material. The Golgi complex was prominent but had no defined arrangement. Observed ultrastructural changes are indicative of intense cell activity and are associated with processes of digestion, synthesis, and excretion as well as of monoterpenes transformation but are not indicative of irreversible cellular damage or death.
The scaling of traits on body size—allometry—is a subject of broad interest in ecology and evolutionary biology, and one in which studies on insects and spiders have featured prominently. Allometric relationships are described with the slope of regressions of trait size (y) on body size (x). A common method—ordinary least squares (OLS) regression—is often expected to underestimate allometric slopes. The reason for this expectation is that OLS regression assumes that x is determined without error, which is expected to bias slope estimates unless the error in y is much larger than the error in x. However, alternative methods such as reduced major axis (RMA) regression suffer from problems of interpretability. Here, we test the hypothesis that OLS regression will underestimate allometric slopes. We used a natural experiment that arose in the course of training to measure insect genitalia, wherein measurement error for genitalia was larger before training than after training, and also differed by a very large amount between traits. Comparing allometric slopes estimated before and after training, and allometric slopes of traits having very different measurement errors, suggests that OLS regression is robust to measurement error in x and that it does not underestimate allometric slopes.
European corn borer, Ostrinia nubilalis (Hübner) (Lepidoptera: Crambidae), displays a larval diapause in response to short photoperiods and is adapted to a variety of local conditions throughout North America. Hence, the effective photoperiod inducing larval diapause will differ among geographic ecotypes. This study considers the inheritance of photoperiodic larval diapause induction by hybridization and backcrossing two latitudinally distinct ecotypes of the European corn borer collected between 41° N, 96° W and 48° N, 96° W and under a range of photoperiods representative of their respective locations: from 14:10 to16:8 (L:D) h. The ecotype adapted to a bivoltine habitat (southeastern Nebraska) exhibited a shorter critical photoperiod (1480 h) than the ecotype (1533 h), originating from a univoltine habitat (northwestern Minnesota). Reciprocal F1 crosses exhibited intermediate values with indication of sex-linked inheritance. In addition, the male parent had significantly more influence on diapause incidence of subsequent progeny than the female. The F2 and backcross progeny further supported the supposition that diapause response is a sex-linked inheritance. The minimum number of genes estimates, and the response from backcross progeny, suggest that diapause response of European corn borer larva may be controlled by only a few loci. The overall results indicated that both ecotypes had adopted unique diapause responses, which ultimately lead to seasonal synchrony in their ecosystems.
This is the first report of sequence-specific microsatellite markers (simple sequence repeats [SSRs]) of fall armyworm, Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae), an economically important pest of crops on the Americas. We isolated 192 microsatellite markers by using pyrosequencing and screened 15 individuals from eight isofamilies collected from three geographical areas: Puerto Rico (PR), Texas (TX), and Mississippi (MS). Isofamilies resistant to Cry toxins from Bacillus thuringiensis (Berliner) (Bacillales: Bacillaceae) also were included. Cluster analysis was performed to determine the potential use of these SSRs in discriminating populations, and colonies were grouped with a reliability of 100% estimated by bootstrap. In this analysis, colonies from TX grouped away from those from PR, but the two MS isofamilies grouped with TX and PR separately. Genetic distance within isofamilies ranged between 0.22 and 0.56, and the minimum distance between isofamilies was 0.83. Unique pattern informative combination (UPIC) scores were calculated, and the 80 SSR markers that had UPIC scores of ≥1 are listed according to their discriminating potential. UPIC scores allow reducing costs by choosing fewer and highly informative markers for future studies. From the best 125 markers, 103 had a maximum of two alleles per sample, making them ideal candidates for population genetic studies. BLAST screening of the sequences points to potential biological meaning of marker polymorphisms. The percentage of alleles shared by the three geographic areas was 14%. The markers reported will significantly enrich the pool of molecular markers available for S. frugiperda. In addition, they could be used for monitoring migration of populations, in the development of biocontrol agents and for management practices in general.
Males of the longhorned beetle Prionus californicus Motschulsky (Coleoptera: Cerambycidae) are significantly attracted to the female-produced sex pheromone (3R,5S)-3,5-dimethyldodecanoic acid. Males respond equally well to the synthetic blend of the four stereoisomers of 3,5-dimethyldodecanoic acid as to the single natural enantiomer, suggesting that the unnatural isomers are not inhibitory. Males of the congener Prionus lecontei Lameere also are attracted to the (3R,5S)-enantiomer but not to the (3S,5R)-enantiomer, suggesting that the (3R,5S)-enantiomer is also an important pheromone component of that species. Here, we report the results of field trials that test the hypothesis that synthetic 3,5-dimethyldodecanoic acid will serve as a general attractant for males of other Prionus species. We conducted field bioassays of synthetic 3,5-dimethyldodecanoic acid at study sites in six different regions of North America and one site in the United Kingdom. Traps baited with the synthetic pheromone blend captured males of P.californicus (southwestern Idaho, southern California, and northwestern Utah), P. lecontei (southern California and northwestern Utah), and six additional species of Prionus: Prionus integer LeConte (southwestern Idaho), Prionus imbricornis (L.) (Georgia), Prionus laticollis (Drury) (Georgia), Prionus linsleyi Hovore (north central Arizona), Prionus aztecus Casey (northern Mexico), and Prionus coriarius (L.) (East Anglia, United Kingdom). These findings demonstrate that synthetic 3,5-dimethyldodecanoic acid can be used to assess the geographic distribution and local abundance of many Prionus species and therefore may be of value for monitoring threatened and endangered species of this genus, and for managing those that are pests.
The New Guinea sugarcane weevil, Rhabdoscelus obscurus) (Boisduval) (Coleoptera: Curculionidae), is a pest of palm plantations, ornamental nurseries, and sugarcane (Saccharum L.). Field and laboratory studies have explored the effects of trap characteristics such as design, size, color, visual and olfactory cues, and location on capture of R. obscurus in date palm plantations and ornamental nurseries at five locations (Dededo, Mangilao, Malojloj, Inarajan, and Yigo) on Guam, USA. Ramp and ground traps captured similarly, and both captured significantly more adults than bucket and pitfall traps. For economy and ease of handling, the ground trap was used for all further experiments. Larger ground traps (≥40 by 25 cm) were more efficient than smaller traps (30 by 15 cm) in capturing adults in the field. Of the eight trap colors tested in the field, brown proved most effective, followed by, in order, yellow, red, gray, blue, black, white, and green; russet was more effective than other shades of brown. Mixing paint of the other colors with brown paint did not significantly improve its performance. In contrast, laboratory color-choice tests indicated R. obscurus preferred black traps over those of other colors and showed no preferences among different shades of black. Again, mixing paint of the other colors with black paint did not significantly improve their performance. Russet brown ground traps baited with pheromone lures caught significantly more adults than did identical traps without lures. Traps strapped to trees caught significantly more individuals than traps placed between trees or away from trees. Russet-brown ground traps 40 by 25 cm seemed to be the most effective at catching R. obscurus in the field, whereas otherwise identical black-colored traps were more efficient indoors.
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