Despite being commonly used as systematic characters earlier this century, relatively few systematists currently use behavioral information for phylogenetic reconstruction. A natural experiment provided by the inferred phylogenetic relationships and host associations of a tribe of ant guest beetles allows for a novel test of the phylogenetic utility of behavior. Historical and current evolutionary forces have acted in opposition during recent behavioral evolution, making it possible to determine the relative evolutionary lability of two general classes of behavioral characters. I dissected the behavioral phenotype into two components and tested for the relative presence of these two opposing forces on each behavioral component. Behavior was broken up into the continuously differing behavioral component (durations of functionally similar beetle behaviors) and the discretely differing behavioral component (species-typical behaviors). Conducting a series of statistic and cladistic tests on each component separately, I concluded that current evolutionary forces primarily determined the continuous behavioral component, because it was most similar among heterogeneric, nestmate beetle species. In contrast, I concluded that ancient evolutionary forces determined the discrete component because it was most similar among congeneric, non-nestmate species. These results support two hypotheses. First, the durations for which behaviors are performed evolve quicker than do species-typical behavioral traits. Second, species-typical behavioral characters are often as nonhomoplastic for phylogenetic reconstruction as are morphological characters.

The phylogenetic relationships among all members of the Drosophila virilis Sturtevant species group were inferred from mitochondrial DNA [partial 16S ribosomal RNA (rRNA), transfer RNA (tRNA)^val, and partial 12S rRNA] sequence data. These data show support for four lineages within the D. virilis species group, which are consistent with previous phylogenetic work performed on the group. However, the relationship among these four groups is not well resolved. These data also suggest that the species D. borealis Patterson is not a monophyletic assemblage, and that the disjunct distribution actually represents two genetically distinct species.

The North American Enchenopa binotata (Say) species complex is a model of sympatric speciation in which phytophagous insects are hypothesized to diverge through host-plant specialization resulting from changes in host plant usage that alter life history timing. A robust phylogeny is needed to evaluate the historical relevance of the prediction that sister taxa differ in critical life-history traits. Phylogenetic analysis using parsimony and likelihood criteria of 2305 nucleotides in sequences from mitochondrial COI, COII, tRNA-Leucine, and 12S genes revealed two pairs of sister taxa. Both pairs of sister taxa differ from each other in the timing of egg hatch in the spring that is mediated by differences in host-plant phenology. Host plant mediated timing of egg hatch results in asynchronous life histories among sister taxa facilitating reproductive isolation. Sister taxa of Enchenopa from Celastrus and from Viburnum differ in their diurnal and temporal spans during which mating occurs. Mating of Enchenopa from Liriodendron takes place after that of its sister species on Cercis. These results support the hypothesis that speciation could have been initiated through a shift to a host plant that alters life-history timing.

What was once considered a single Holarctic species of green lacewing, Chrysoperla carnea (Stephens), has recently been shown to be a complex of many cryptic, sibling species, the carnea species group, whose members are reproductively isolated by their substrate-borne vibrational songs. Because species in the complex are diagnosed by their song phenotypes and not by morphology, the current systematic status of the type species has become a problem. Here, we attempt to determine which song species corresponds to Stephens’ 1835 concept of C. carnea, originally based on a small series of specimens collected in or near London and currently housed in The Natural History Museum. With six European members of the complex from which to choose, we narrow the field to just three that have been collected in England: C. lucasina (Lacroix), Cc2 ‘slow-motorboat’, and Cc4 ‘motorboat’. Ecophysiology eliminates C. lucasina, because that species remains green during adult winter diapause, while Cc2 and Cc4 share with Stephens’ type a change to brownish or reddish color in winter. We then describe the songs, ecology, adult morphology, and larval morphology of Cc2 and Cc4, making statistical comparisons between the two species. Results strongly reinforce the conclusion that Cc2 and Cc4 deserve separate species status. In particular, adult morphology displays several subtle but useful differences between the species, including the shape of the basal dilation of the metatarsal claw and the genital ‘lip’ and ‘chin’ of the male abdomen, color and coarseness of the sternal setae at the tip of the abdomen and on the genital lip, and pigment distribution on the stipes of the maxilla. Furthermore, behavioral choice experiments involving playback of conspecific versus heterospecific songs to individuals of Cc2 and Cc4 demonstrate strong reproductive isolation between the two species. Comparison of the adult morphology of song-determined specimens to that of preserved specimens in the original type series and in other collections in The Natural History Museum, London, indicate that the ‘true’ Chrysoperla carnea (Stephens) is Cc4. Cc2 cannot be confidently associated with any previously described species and is therefore assigned a new name, Chrysoperla pallida sp. nov., and formally described.

The life history of the emesine reduviid Pseudometapterus umbrosus (Blatchley) was studied in southern Illinois from February 1999 to November 2000, and the immature stages were described. The bug also was reared from egg to adult under controlled laboratory conditions. This univoltine species occurred on the rock faces of sandstone bluffs often in association with plants and spider webs. Adults and nymphs preyed primarily on small flies. Adults overwintered within fallen leaves on the bluff outcroppings, emerged in early April, and began feeding and reproducing shortly thereafter. Eggs were found from early May to late October and were deposited on the leaves and stems of Heuchera parviflora Bartling. Nymphs were found from early June to early September. New adults appeared in mid-July and remained active until early October. This species was reared in the laboratory on adult Drosophila sp. at 26 ± 3.0°C under a photoperiod of 16:8 (L:D) h. The incubation period averaged 13.25 d; eyespots appeared in ≈7 d. The five stadia averaged 11.86, 11.77, 12.44, 15.35, and 18.88 d, respectively. The instars can be distinguished by differences in several anatomical features including body length and width.

South American populations of Trimerotropis pallidipennis Burmeister are polymorphic for pericentric inversions. In this species, rearrangement frequencies follow repetitive patterns of distributions along different geographic areas, which are determined by altitude, minimum temperature, and humidity variables. The current article reports the analysis of random amplified polymorphic DNA (RAPDs) in five populations of T. pallidipennis and shows the possible relationships of this kind of molecular variability with inversion and enzyme polymorphisms. Both comparisons of RAPDs versus chromosome and RAPDs versus enzyme genetic distances yielded significant results, indicating that the degree of differentiation between pairs of populations is significantly similar when all three types of variability are compared with each other. Specifically, the differentiation for loci amplified by some of the primers is significantly correlated with the differentiation in humidity conditions. Therefore, RAPD loci frequencies tend to follow similar patterns of variations as chromosome and enzymatic variability. Inversions are of evolutionary significance because they can generate supergenes that preserve special genetic sequences. A population of T. pallidipennis at high altitudes, which is monomorphic for basic sequences at all chromosomes, will not have the same allele sequence as a population at low altitudes with fixed inverted chromosomes. Because all seven inversions involve a good portion of the genome, a variation between supergenes that differentiate populations is expected to be observed when many random fragments of DNA are amplified, because an eventual recognition sequence of the primers sited into the inversion may be altered. The significance of the congruence between enzymatic and RAPD variability is also discussed.

For most species of ants, newly mated queens found new colonies from stored body reserves, and without the assistance of workers. Consequently, until the first batch of colony members hatches, newly mated queens face a potential shortage of labor for brood care. The purpose of this study was to describe the brood rearing strategies of newly mated monogyne Solenopsis invicta queens, under controlled laboratory conditions, to determine how they compensated for the lack of worker labor in rearing the first batch of colony members. Newly mated S. invicta queens were collected (n = 60) and reared individually in artificial nests in the laboratory under optimal incubation conditions. Using video-technology, brood care activity by newly mated queens was quantified and compared with brood care activity of mature queens who were incubated with workers. In addition, newly mated queens and their offspring (i.e., the incipient colony) were censused biweekly for 6 mo to determine the ontogeny of the adult:larva ratio. Results from this study revealed that newly mated queens spent 65% of their time engaged in brood care activities; queens incubated with workers spent <1% of their time tending brood. Newly mated queens laid two kinds of eggs, viable and trophic. Trophic eggs were ingested by the queen, and then regurgitated to larvae. In the second phase of colony founding, after the first worker offspring hatched, the adult:larva ratio was >1:1. Consequently, larvae were never in competition with each other for worker attention. In summary, this study revealed that newly mated queens were endowed with a suite of compensatory brood rearing strategies enabling them to succeed in founding a colony in the absence of worker labor.

Clutch size variation of a leaf mining moth Paraleucoptera sinuella Reutti was investigated on two host plants, Populus sieboldii Miquel and Salix miyabeana Seemen. We found that female moths oviposited egg clutches with different size on the two host plants and that clutch size was correlated with leaf area between host species. Therefore, we concluded that females are adjusting clutch size in response to variation in resource availability for offspring. Positive correlation was also found between clutch size and leaf area within host species, however, the relationship was weak. Expected clutch size was determined from estimates of leaf area consumed by a larva until pupation. Females laid significantly smaller clutches than the expected size that could be supported by a single leaf on both host plants. We discussed how the females determined clutch 2size in response to resource availability.

Mesochorus curvulus Thomson was the only secondary parasite (hyperparasite) reared from six primary parasites (Braconidae: five Peristenus spp., one Leiophron sp.) collected in the field, in their mirid hosts. These six braconids parasitized nymphs of four species of phytophagous plant bugs, two (Leptopterna, Trigonotylus) feeding on forage grasses, and two (Adelphocoris, Lygus) feeding on alfalfa. The principal samples were collected weekly and biweekly on commercial farms in northwestern New Jersey over a 10-yr period. Although M. curvulus attacked six primary parasite species, it preferred Peristenus pallipes (Curtis), which in turn preferred the two non-native, grass-feeding mirids. These preferences suggest that both P. pallipes and M. curvulus are also not native to North America. Rates of hyperparasitism were higher in the most abundant primary parasites, so were density-dependent. The low hyperparasitism rates observed (1–11%) indicate that Mesochorus does not have a strong negative effect on the primary parasites, several of which are useful in biological control of plant pests. Diapause in Mesochorus appears to be regulated by the primary parasite rather than by photoperiod. The sex ratio of M. curvulus was normal (55% female).

The Asian longhorned beetle, Anoplophora glabripennis (Motschulsky), was recently introduced to the United States and has the potential to destroy many urban and forest trees. A successful artificial diet and rearing protocol are urgently needed, because research with this wood-boring beetle can be conducted only in the confined areas of quarantines. We compared larval growth and adult parameters using three artificial diets, one developed in China for A. glabripennis and two developed for other members of the Lamiini. The only difference in performance of larvae and adults reared on the three diet types was that nondiapausing larvae reared on Monochamus carolinensis (Olivier) diet needed less time to pupate than nondiapausing larvae on A. glabripennis diet. We further evaluated substituting the phloem–cambium of sugar maple, Acer saccharum Marshall, with sawdust or cellulose. Males grew fastest on diets with sawdust or phloem–cambium and remained as pupae for the shortest period of time on A. glabripennis diet. Females grew faster on diets with cellulose than sawdust and lived longest on A. glabripennis diet. The published A. glabripennis artificial diet, modified by increasing the water content from 50.0 to 64.6% (wt:wt) and substituting the phloem–cambium component with cellulose, was the optimal diet tested. A rearing protocol used to maintain our colony is included.

The influence of temperature and photoperiod on the preoviposition duration and oviposition of the strawberry root weevil, Otiorhynchus ovatus (L.), were studied in strawberry (Fragaria X ananassa Duchesne Variety ‘Totem’). In one experiment, adults were subjected to constant temperatures from 3 to 33°C at 3°C intervals and in another experiment adults were subjected to four photoperiods at 21°C. Oviposition was monitored for all treatments. Adults fed at all temperatures from 3 to 33°C and oviposited at temperatures between 18 and 30°C. The longest preoviposition period (32 d) and the fewest total number of eggs (2) were observed at 18°C. The shortest preoviposition period (15 d) and the largest total number of eggs (282) were observed at 27°C. A temperature range of 21–27°C appeared to be optimum for oviposition. Within this range, the lowest mortality, shortest preoviposition period, longest oviposition period, and greatest total number of eggs were observed. Weevils oviposited at all photoperiods. Length of preoviposition period and egg viability did not vary significantly among photoperiod treatments. Adults oviposited an average of 15 eggs at 12:12 (L:D) h and an average of 148 eggs at 18:6 h (L:D) h. A linear regression model predicted an increase of 23 cumulative eggs laid for each 2-h increase of daylength.

Hemolymph flow patterns, deduced from movements of single plasmatocytes (PLs) in the heart-dorsal vessel system were observed in developing embryos of the waterstrider Gerris paludum insularis Motschulsky. Video images of single moving PLs successively captured at 0.033 s intervals were followed to reveal their passage during each cardiac cycle, and a structural cardiogram was used to analyze the movements of individual PLs in terms of the cycle. In hearts of G. p. insularis embryos, cultured for 80 h after katatrepsis (K 80 h embryos; K stands for katatrepsis), forward flow with systole and backward flow with diastole occurred alternatively during each cycle. In K 100 h embryos, however, forward flow was observed only with systole and ceases at other times in the cycle. Velocity of single moving PLs in K 80 h embryos, estimated from distance traversed by PLs for each 0.033 s, was smaller than that in K 100 h embryos similarly estimated. This might indicate that the force generated by each systolic contraction in the heart of G. p. insularis embryos increased as embryogenesis advanced. Velocity of single moving PLs was suggested as a useful parameter to assess functional development of embryonic heart in insects.

The ultrastructure of the globular papillae located along the inner side of the forceps of the two flying stages, imago and subimago, of male mayflies belonging to Ecdyonurus venosus (F.) is described. The external shape of the globular papillae varies with their position on the forceps’ segments and the stage. In longitudinal section, the globular papillae of the imago and subimago have a single dendrite ending in a tubular body, a feature consistent with their function as mechanosensory sensilla. During mating, the mechanical pressure on the forceps may be sensed by the cuticular surface of the papillae and transmitted to the tubular body. In the subimago, the globular papillae have a pointed apex and are less numerous. Another kind of sensillum, hairs having the typical organization of mechanoreceptive bristles, are scattered on the forceps of both imago and subimago.

Different genes have been used to evaluate the genetic divergence of closely related species or populations of insects. The taxonomic level at which specific genes or nucleotide regions are useful varies across taxa. This study assesses the relative phylogenetic usefulness of a segment of a noncoding ribosomal region (ITS2) in separating populations of the parasitoid Ageniaspis citricola (Hymenoptera: Encyrtidae) from different geographic areas (Australia and Taiwan). Intra- and interindividual variations in ITS2 sequence and length have affected previous phylogenetic studies with other arthropods. To determine whether these variations would affect our phylogenetic studies, clones (2–3/individual) containing ITS2 polymerase chain reaction (PCR) products were sequenced from two to five individuals for each of the two populations. Three clones from one A. fuscicollis (a species present only in Europe) individual were used for comparison. Intra- and interindividual variations in ITS2 sequence and length were present in the three Ageniaspis populations. Intraindividual sequence variation was sometimes greater than between individuals in each Ageniaspis population. All clones isolated from a single individual were different, and no single variant was common to all wasps in any Ageniaspis population. The variation in sequence and length of the ITS2 region in Ageniaspis populations suggests that concerted evolution has not homogenized all rDNA copies within individuals. Despite the level of intraindividual variation found, the sequences of this ITS2 region were phylogenetically informative and defined the three populations (A. citricola Australian and Taiwanese, and A. fuscicollis). These results confirm previous molecular work using RAPD-PCR and Actin genes and suggest that the two populations of Ageniaspis from Australia and Taiwan are cryptic species.

Phorid flies in the genus Pseudacteon affect the foraging and defensive behaviors of their host, the red imported fire ant, Solenopsis invicta Buren. Field observations of Pseudacteon species indicated interspecific variation in attack behavior. Here, we assess whether differences in attack behavior and ant response might assist in prioritizing species for biocontrol. We studied the oviposition behavior of eight phorid fly species and determined how attack by each influenced the normal behavior of the red imported fire ant. The fly species tested were: Pseudacteon borgmeieri Schmitz, P. curvatus Borgmeier, P. nudicornis Borgmeier, P. obtusus Borgmeier, P. solenopsidis (Schmitz), P. tricuspis Borgmeier, P. litoralis Borgmeier, and P. wasmanni (Schmitz). Of these, P. borgmeieri attack interfered with normal red imported fire ant worker behavior the most, whereas P. curvatus had the least effect. Because the supposed effectiveness of phorids as biocontrol agents depend on their ability to interfere with normal fire ant behavior, these results suggest that some species of phorids would be better candidates for biocontrol than others. Our results combined with results from other studies examining host specificity of phorids suggest that P. tricuspis and P. obtusus are excellent candidates for biocontrol of the red imported fire ant in geographical areas where polygyne colonies dominate, such as Texas. Conversely, where monogyne colonies dominate, such as Florida, P. litoralis should be considered.