Several revisions of the taxonomy of the scolytid genus Dendroctonus have been reported during the last century. These have been based on the external morphology and biology of adults, karyology, and most recently molecular genetics. Using karyological data—chromosomal number and mechanism of sex determination—from 119 Dendroctonus populations representing 16 of the 19 species currently recognized, we determined rate of chromosomal evolution and evolutionary phases of this genus. The karyological formulae vary from 5 AA neo-XY (2n = 12) to 14 AA Xyp (2n = 30). The modal number of chromosomes is 2n = 30, with a mean 2n value of 23.37 and coefficient of variation of 31.67%. These values indicate that Dendroctonus has a high rate of chromosomal diversity and that its evolutionary phase is of regression. Theoretically, the genus should be composed of specialist species with relatively low chromosomal numbers; however, this is not the case. We also used chromosomal evidence to examine the suspected Mexican origin for Dendroctonus. We posed two hypotheses to explain the karyological diversification and current distribution of Dendroctonus species. The first considered that diversification of the karyotype originated from species with 14 AA Xyp during its dispersion southward with its hosts (Pinus spp.) in North America. The second assumed that karyological diversification of Dendroctonus occurred during the dispersion of the genus toward Eurasia and southward in North America and that the increases and decreases in number of chromosomes originated from an ancestral karyotype between 18 and 22 chromosomes. Evidence for each hypothesis is discussed.

The distributional pattern of the four known karyotypes (male 2n = 37, 39, 43, 45) of the Cryptocercus punctulatus Scudder species complex is reported, based on 71 sites in the Southern Appalachian Mountains with an emphasis on western North Carolina. Populations with different karyotypes are geographically structured in a mosaic, with at least one karyotype occurring in two disjunct regions. Abrupt geographic transitions between karyotypes suggest a parapatric distribution. We found no overlap in the distribution of the different karyotypes, as recently suggested. Although the boundary zones between karyotypes do not appear to coincide with physical or ecological barriers to dispersal, several transitions between karyotypes occur on or near the highest mountains in the southern Appalachians. We suggest that the different karyotypes arose by vicariance, with current boundaries formed by secondary contact when populations isolated in glacial refugia subsequently spread into high-mountain habitats. Because of their dependence on mature mesic forests, populations of the cockroach likely advance up and down mountainsides in cycles of advances and retreats dictated by climatic oscillations that raise and lower the timberline. We discuss the taxonomic status of the different karyotype groups in the C. punctulatus complex, and conclude that more exacting evidence is required to establish if species-level status is warranted. The conclusions of certain earlier studies are weak because, among other things, karyology was not examined in the sampled specimens, including those designated as types.

The Holarctic Archips xylosteana Group consists of at least 18 morphologically similar species in the Nearctic, three of which were synonymized with A. argyrospila by Razowski and subsequently returned to species status, two that were described since 1986 but are clearly related to A. argyrospila, and an additional Western clade of A. argyrospila haplotypes that Razowski had not seen. We examined the morphology of all described Nearctic Xylosteana Group members plus one undescribed species, as well as DNA variation in a 816 bp segment of the mitochondrial COI gene for 17 of these species. We also examined three of five species of Archips from the Packardiana Group (=Archippus Freeman), and three outgroup genera (Argyrotaenia Stephens, Clepsis Guenée, and Choristoneura Lederer). Parsimony analyses of the combined molecular and morphological data sets gave better resolution and a better supported tree than did analyses of any single data set. All analyses revealed five species groups, rendering paraphyletic the Xylosteana Group as previously defined. An updated systematic list of Nearctic Archips is provided. We discuss the possibility that our data could support the resurrection of the genus Archippus from synonymy and the recognition of the Cerasivorana Group and the Purpurana Group as new genera. We have elected to leave the genus intact pending future investigations that include the additional Palaearctic members of the group.

The Caribbean treehopper genus Antillotolania Ramos, classified in the subfamily Stegaspidinae, is redescribed based on adult morphology. Antillotolania doramariae Ramos, the type species, is redescribed and illustrated; descriptions and illustrations are also given for A. microcentroides, new species from Guadeloupe and the British Virgin Islands, and A. extrema, new species from Puerto Rico. A key for the identification of adults is provided for the genus.

A new species of podapolipid mite, Eutarsopolipus platyni, is described, illustrated, and compared with related species of Eutarsopolipus in the biunguis group. The species is an ectoparasite of Platynus brunneomarginatus Mannerheim collected from Alameda, Marin, and Santa Clara Counties in California, U.S.A., and Nanaimo, British Columbia, Canada. This is the first record of the biunguis group of Eutarsopolipus in western North America. A key to the seven species of the biunguis group of Eutarsopolipus is provided.

An unusual new species of Zygothrica, Z. desallei, is described from Ecuador. This species possesses three supernumerary crossveins extending from vein R2 3 to the costa. Such a phenotype, while observed in other drosophilid genera such as Jeannelopsis and Scaptomyza (Tantalia), has not been previously observed in Zygothrica.

Two species of Hybosoridae, Hybosorus illigeri Reiche and Pachyplectrus laevis LeConte, are distributed in the United States. For the introduced species H. illigeri, three new country records are reported (Dominican Republic, Nicaragua, and Venezuela); six new state records are recorded in the United States (Arkansas, Arizona, Kansas, Missouri, New Mexico, and Virginia); and 10 new state records are reported in Mexico (Baja California Sur, Chiapas, Michoacán, Nuevo León, Sinaloa, Sonora, Tamaulipas, Veracruz, Querétaro, and Yucatán). Information on the predatory habits of H. illigeri and a report as a turfgrass pest in the state of Arizona are provided. Pachyplectrus laevis is redescribed, and information on its biology and distribution is provided. A key to the species is provided along with diagnostic illustrations.

RESUMEN Dos especies de Hybosoridae, Hybosorus illigeri Reiche y Pachyplectrus laevis LeConte se distribuyen en los Estados Unidos. Se reporta para la especie introducida, Hybosorus illigeri, nuevos registros en tres paises (República Dominicana, Nicaragua y Venezuela); seis nuevos registros en estados de los Estados Unidos (Arkansas, Arizona, Kansas, Missouri, New Mexico, y Virginia); y diez nuevos registros en estados de Mexico (Baja California Sur, Chiapas, Michoacán, Nuevo León, Sinaloa, Sonora, Tamaulipas, Veracruz, Querétaro y Yucatán). Se provee información sobre los hábitos predadores de Hybosorus illigeri. Pachyplectrus laevis es redescripta y se provee información sobre su biología y distribución. Se provee una clave para las especies junto con ilustraciones para su diagnosis.

In a recent revision of Spilodiscus Lewis, several species were removed from that taxon to Hister L. These five species, Hister militaris Horn, H. lucanus Horn, H. pioti Marseul, H. humilis Fall, and H. sarcinatus Lewis, form a clade within Hister and are not closely related to Spilodiscus (though species in both groups commonly exhibit red elytral markings). Here the species are revised, and comments on some unusual facets of their morphology and biology are discussed in light of a tentative phylogenetic hypothesis.

The eight species in the genus Palaeophileurus are reviewed, including the description of two new species from Peru: P. carbo Ratcliffe and P. erebus Ratcliffe. The diagnostic male parameres for all species are illustrated, and a distribution map is provided.

RESUMEN Se revisan las ocho especies del género Palaeophileurus, y se incluye la descripción de dos nuevas especies de Perú: P. carbo Ratcliffe y P. erebus Ratcliffe. Se proveen ilustraciones diagnósticas de los parámeros de todas las especies, y una mapa de distribución.

The bamboo bug Notobitus meleagris F. shows two types of mating aggregation: harem including a male and one or more females, and multi-male including some males and females. Both types of mating aggregations were formed only on young bamboo shoots. The mean body size of males was significantly smaller in multi-male aggregations than in harem aggregations, but female size was independent of aggregation type. There was a significant positive correlation between the body size of males and the number of females in harem aggregations that formed in association with male-male aggressive contests. More females were attracted to thicker than thinner bamboo shoots, where larger aggregations formed. Multi-male aggregations were observed more on thicker than thinner shoots. Multi-male mating aggregations may occur when females cannot be economically defended.

The pollination effectiveness (floral visitation rate, percentage of flowers pollinated, and pollen deposition) of indigenous and introduced bees visiting lowbush blueberry (Vaccinium angustifolium Aiton) was studied in Nova Scotia from 1992 to 1994. Floral visitation rate alone was not a good indicator of pollination effectiveness, as not all floral visits resulted in successful pollination events. As a group, pollen-harvesting taxa pollinated >85% of flowers visited as compared with under 25% for nectar foragers. Equivalencies derived from floral visitation rates and pollination percentages show that the most effective pollen-harvesters, Bombus spp. queens and Andrena spp., would pollinate 6.5 and 3.6 flowers, respectively, in the time it would take a nectar-foraging honey bee, Apis mellifera L., to pollinate a single flower. Average pollen deposition for nectar-foragers (A. mellifera and Megachile rotundata F.) did not exceed 13 tetrads per visit, which was significantly less than all pollen-harvesters. Among pollen-harvesters, Bombus spp. workers, M. rotundata and Halictus spp. deposited moderate stigmatic loads (34, 28, and 26 tetrads, respectively), whereas Bombus spp. queens and Andrena spp. deposited >45 tetrads per single visit. Pollination equivalencies show A. mellifera would have to visit a flower four times to deposit the same amount of pollen as single visits by Bombus spp. queens or Andrena spp.

The usefulness of the control region of mtDNA as a tool for the study of population structure in the mosquito Aedes aegypti (L.) was analyzed. Population samples were taken from several geographic areas of Argentina; one additional sample from the city of San Juan, Puerto Rico, was included for comparison. In individual mosquitoes, the A T-rich and the COII-COIII regions were amplified by polymerase chain reaction using universal insect primers. Restriction fragment-length polymorphisms were investigated from amplification products. In the A T region, three amplified fragments of different total length were obtained (of ≈2,500, 2,300, and 2,100 bp). The enzymes Ssp I, Dra I, Pac I, and Apo I produced polymorphic patterns. Including total fragment length as a variable, eight different haplotypes were resolved for Argentinian populations, some presenting a restricted geographic distribution. The coding COII-COIII region revealed very low polymorphism. Although 11 restriction enzymes were employed to analyze this region, only two different haplotypes were found, one of them shared by populations as distant as Buenos Aires and San Juan. We demonstrated that total length and restriction fragment-length polymorphisms within the noncoding A T-rich region, but not the coding COII-COIII fragment, are informative to discriminate Aedes aegypti populations. Mean F_ST value (0.48, P < 0.001) indicates an important degree of differentiation among populations. Absence of an isolation by distance pattern was demonstrated.

Polymerase chain reaction (PCR) technique was used to develop a specific molecular marker for detection of immature stages of the egg parasitoid Anaphes iole Girault developing within its host, Lygus lineolaris (Palisot de Beauvois). Ribosomal DNA sequences for the internal transcribed spacer 2 (ITS2) were cloned and sequenced from adult A. iole and L. lineolaris. PCR amplification of genomic DNA using primers designed on the basis of these rDNA sequences, followed by agarose gel electrophoresis, successfully detected eggs and larvae of the parasitoid within L. lineolaris eggs. This molecular method is highly specific and sensitive. A 661-bp wasp DNA fragment was consistently amplified from pure DNA extracted from a single wasp, from a DNA mixture prepared from a wasp and an L. lineolaris egg, and from a DNA mixture prepared from a wasp, an L. lineolaris egg, and alfalfa tissue. The presence of plant tissue did not hinder detection of A. iole within host eggs. With this PCR technique, as low as 5 × 10⁻⁶ wasp DNA equivalent (1.2 pg DNA) could be easily detected. The PCR technique provided more rapid detection of parasitism rates than observed by rearing parasitized host eggs in artificial oviposition packets. PCR technology shows promise for early and sensitive detection and identification of single and multiple species of egg parasitoids in agricultural and natural systems.

Normal eye color of the tarnished plant bug, Lygus lineolaris (Palisot de Beauvois), is dark purplish-black. A strain homozygous for a new mutation, red eye color, was established and reared in the laboratory for >5 yr. The mutant phenotype is controlled by a single autosomal recessive allele. The gene symbol assigned to this new mutant is r. Laboratory tests showed that egg production and egg viability in the red-eye mutant females were not different from that of normal-eye females. Expression of the red-eye mutation was not found in extensive samples of wild populations in the Mississippi River Delta, and was rare in populations near Crossett, AR, where the original mutant was found. The mutant strain could be of use as a genetic marker in studying reproductive behavior and population dynamics of this important pest species.

The migratory locust, Locusta migratoria Linné, shows not only prolonged copulation but also prolonged precopulatory associations between males and females. To understand the evolutionary significance of these behaviors, sperm competition success, measured by the P₂, (i.e., the proportion of offspring sired by the second male to mate), was analyzed using the genetic marker albino. The precopulatory behavior has been proposed to guard a female or ensure timely mating. We report here that precopulatory mounting has a function other than guarding or just waiting in this locust: prolonged precopulatory mounting increases the length of copulation, which in turn increases the P₂. Lengths of precopulatory mounting and copulation, as well as nearly absent postcopulatory mounting, were little influenced by the presence of a rival male. The observed large variation in P₂ indicates that previously proposed mechanisms for sperm competition are not mutually exclusive, but all could occur in this species.

A nested polymerase chain reaction protocol yielded positive detection of the maternally inherited cytoplasmic proteobacterium Wolbachia in total genomic DNA from coffee berry borers collected in Benin, Brazil, Colombia, Ecuador, El Salvador, Honduras, India, Kenya, Mexico, Nicaragua, and Uganda. Wolbachia was not detected in specimens from Cameroon, the Dominican Republic, Indonesia, Jamaica, and Peru. Amplified bands from India and Brazil were cloned and sequenced. The 438-bp sequence clearly conformed to Wolbachia group B and was nearly identical to that of Ephestia kuehniella. The possible implications of Wolbachia infection in the coffee berry borer are discussed.

Hermetia illucens (L.) was reared on three larval diets to determine their effects on preimaginal development and selected adult life-history traits. Prepupal and adult characteristics were examined for individuals reared on each diet and compared with field-collected prepupae and corresponding emergent adults. Diet did not significantly influence development or survivorship to the prepupal stage. However, adult emergence for all diets was significantly less than that determined for the wild population. Development time from egg to adult for individuals reared on the diets at 27°C ranged from 40 to 43 d with the larval stage lasting 22–24 d. We observed >96% larval survivorship to the prepupal stage and 21–27% adult emergence. Females accounted for 55–60% of emergent adults across treatments. Specimens reared on each diet were reduced in size, longevity, and calorie content in comparison to specimens from the wild population. Males within diet treatments and field-collected specimens were significantly smaller than females and emerged 1–2 d before females. Additionally, males reared on the diets and provided water lived for 9 d, whereas females lived for 8 d. This information indicates the diets might be used for rearing soldier flies. However, further refinement is needed to produce adults similar to those found in nature.

In separate experiments, Bemisia tabaci (Gennadius) from Namulonge, Uganda, was taken from a colony reared on uninfected cassava plants (Manihot esculenta) Crantz. (nonviruliferous whiteflies) and a colony reared on cassava plants infected with East African cassava mosaic virus (viruliferous whiteflies) and allowed to oviposit on uninfected and East African cassava mosaic virus-infected cassava plants for 3 d. There were no significant differences in the number of eggs oviposited and in the number of first instar, second/third instar collectively, and fourth-instar nymphs at different periods on the uninfected and infected plants. The number and sex ratio of eclosed adults as well as the total developmental period were also not significantly different between B. tabaci developing on uninfected or infected plants. These were the findings where either nonviruliferous or viruliferous whiteflies were allowed to oviposit on the plants. Highest mortality occurred on fourth instars developing on uninfected plants where either nonviruliferous or viruliferous whiteflies were allowed to oviposit. This was also the case on the infected plants, where oviposition was by viruliferous whiteflies. Based on regression equations, highest mortality on fourth instars was characterized as population density-independent. Mortality was highest on first instars developing on the infected plants where nonviruliferous whiteflies were allowed to oviposit, and was characterized as population density-dependent. A follow-up experiment showed no significant differences in the total number of nymphs and empty pupal cases over two generations for whiteflies developing on uninfected or infected plants. These data indicate that plants infected with East African cassava mosaic virus will not result in a population boost of B. tabaci. This is quite unlike what has been reported of plants infected with the putative recombinant virus involving East African cassava mosaic virus in combination with African cassava mosaic virus.

Mixed-feeding habits, such as zoophytophagy, make the ecological roles of many species of insects, especially hemipterans, difficult to assess. To understand the feeding adaptations of the predacious plant bug Deraeocoris nebulosus (Uhler), the digestive enzymes from the salivary glands and anterior midgut were analyzed, and the mouthpart stylets were investigated with scanning electron microscopy. Evidence of trypsin-like enzyme, α-glucosidase, and pectinase were found in the salivary glands. Low levels of trypsin-like, chymotrypsin-like, elastase-like, and pectinase activity, with high levels of α-amylase and α-glucosidase activity, were found in the anterior midgut. The insect’s right maxillary stylet has two rows of at least six recurved barbs on the inner surface pointing away from the head. This plant bug is equipped mainly for zoophagy but has enzymes that would allow some degree of phytophagy.

Genetic correlations for behavioral characteristics and forewing length of worker honey bees, Apis mellifera L., were estimated. All characteristics associated with defensive behavior were correlated with each other. The tendency of bees to fly off the combs was correlated with their tendency to run on the combs, and with stinging behavior. Tendency to run was positively correlated with tendency to hang from combs, and with hygienic behavior, but was negatively correlated with forewing length. Forewing length was negatively correlated with hygienic behavior, but it was not significantly correlated with stinging behavior. The correlations obtained suggest that smaller bees have higher activity levels than larger bees. The implications of these results on the adaptive success of Africanized honey bee populations to tropical environments and on selective breeding are discussed.