The small Neotropical riodinid genus Minstrellus (Lepidoptera: Riodinidae) is described and revised. It seems to be most closely related to Pseudonymphidia Callaghan, in the incertae sedis section of the Riodininae. A phylogenetic analysis of its four species, using 11 characters of adult morphology, generated a single most parsimonious cladogram with the following structure: grandis (nivosa (leucotopus emphatica)). The species watkinsi d’Abrera, like all the taxa of Minstrellus, was described in Ematurgina Röber (a synonym of Synargis Hübner) and briefly subsequently treated in Zelotaea Bates, but it is here transferred to Machaya Hall & Willmott (n. comb.). The taxon emphatica Stichel is raised from a subspecies of leucotopus Stichel to the rank of species (n. stat.), and the name candida Le Cerf is synonymized with emphatica (n. syn.).

Third instars of the diving beetle Notaticus fasciatus Zimmermann (Coleoptera: Dytiscidae) are described for the first time, representing the first description of larvae from Aubehydrini, the only remaining tribe of Dytiscinae unknown as larvae. The description is based on larvae suspected to be N. fasciatus collected in French Guiana. The specimens were associated with adults by analyzing an 806-bp fragment of cytochrome c oxidase I. Adults of N. fasciatus and 19 other species were included representing all tribes and most species of Dytiscinae found in northern South America with multiple representatives of some for a total of 33 terminals. Data were analyzed using parsimony and p-distances. The parsimony analysis resulted in a single tree. The unknown larva grouped with adult specimens of N. fasciatus (bootstrap 100%). Distance between them averaged 0.01 (0.01–0.02) compared with 0.02 (0–0.06) between other conspecifics and 0.13 (0.05–0.17) between different species. N. fasciatus larvae differ from other Dytiscinae in the following characters: 1) head capsule subtriangular; 2) occipital suture absent; 3) anterior margin of frontoclypeus convex; 4) dorsal margin of foramen magnum straight; 5) dorsal pair of stemmata unmodified; 6) antennomere I, maxillary palpomere I, and labial palpomeres I and II not subdivided; 7) maxillary palpomere II subdivided; 8) ligula absent; 9) galea well developed; 10) natatory setae present on dorsal margin of coxae, absent along ventral margin of trochanters and tarsi; 11) tarsal claws not serrate; 12) abdominal tergites fully developed; and 13) urogomphus well developed, shorter than last abdominal segment, and without natatory setae.

The genus Megamelus Fieber (Hemiptera: Delphacidae), frequently associated with aquatic plants, includes four species in South America. One of these species, Megamelus scutellaris Berg, was the only species previously recorded in Argentina. In recent explorations in wetlands of South America (northeastern Argentina, eastern Peru, and southeastern Brazil), five species on Pontederiaceae were studied: Megamelus electrae Muir, Megamelus iphigeniae Muir, M. scutellaris, Megamelus timehri Muir, and Megamelus bellicus Remes Lenicov & Sosa sp. nov. Male holotypes of M. electrae, M. iphigeniae, and M. timehri were redescribed; females of both winged forms and brachypterous males of M. electrae and M. iphigeniae, and the female allotype of M. timehri, were described for the first time. M. bellicus is new for science, and it is described based on the following pattern combination: front coloration, anal segment with asymmetrical spine-like processes, shape of pygofer and aedeagus processes in the male, length of the ovipositor, and shape of the valvifer VIII. A key to distinguish the five South American species, based on male and female genitalia and the external morphology, is presented. This work is an update of knowledge on this genus, incorporating new specific diagnostic characters such as the length of ovipositor, shape and position of valvifer VIII, shape and denticulation of the first and second valvulae, and coloration pattern. Further information on host plants, geographical distribution, and biological data are reported.

Distributions of chaetodactylid mites (Acari: Chaetodactylidae), obligate associates of long-tongued bees of the families Apidae and Megachilidae, largely correspond to those of their hosts. Early derivative lineages of mites (Centriacarus gen. n. and Roubikia) are restricted to the endemic Neotropical apid bee genera Centris and Roubikia, respectively. Phylogenetically derived mite lineages are worldwide in distribution: Sennertia species are associated with carpenter bees (Ceratina and Xylocopa), and Chaetodactylus species are associated with nine megachilid and five apid bee genera. In contrast, mites of the genus Achaetodactylus are known exclusively from African Ceratina hosts. Reconstruction of the historical biogeography of the group, including the newly described early derivative genus Centriacarus, is conducted for the first time. Present distribution and host associations of chaetodactylids can be best explained by host shifts and intercontinental dispersals of phylogenetically basal groups. The Neotropical region is most likely to have been the ancestral area of this mite family. We describe six new early derivative taxa from the Neotropics, the center of origin and a biodiversity hotspot for chaetodactylids: Centriacarus turbator sp. n. (ex Centris vittata; Brazil, Peru, Colombia, Panama, Mexico); Centriacarus guahibo sp. n. (ex Centris sp.; Venezuela); Roubikia officiosa sp. n. (ex Tetrapedia maura; Mexico); Roubikia imberba sp. n. (ex Tetrapedia sp., and cleptoparasites Coelioxoides waltheriae and C. exulans; Argentina); Chaetodactylus melitomae sp. n. (ex Melitoma marginella, M. segmentaria; Mexico, Honduras); and Chaetodactylus lassulus sp. n. (ex Trichothurgus dubius, T. herbsti; Chile).

The genus Burtinus is revised. Its two species, Burtinus notatipennis (Stål) and Burtinus luteomarginatus Maldonado, may be distinguished by differences in features of the antenna, degree of hind-coxal separation, ovipositor, and genital capsule. B. notatipennis is widespread in Central and northern South America (and Trinidad), and it also occurs in the Bahamas, Arizona, Texas, and Florida. B. luteomarginatus, hitherto known only from the type locality (Puerto Rico), is found throughout elsewhere in the Greater Antilles (Cuba, Dominican Republic) and in Guana (British Virgin Islands). We give several new country records.

The 10 species of Cybocephalidae occurring in Mexico are revised. Included are redescriptions of Cybocephalus aciculatus Champion, Cybocephalus schwarzi Champion, and Pycnocephalus metallicus Sharp, and descriptions of four new species: Cybocephalus beverlyae, Cybocephalus championi, Cybocephalus huastecus, and Cybocephalus zakotus. The male of P. metallicus is described for the first time. A key to species; illustrations of morphological features, including detailed drawings of male genitalia; and distribution data are provided.

We studied geographical body size variation in 23 populations and sexual size dimorphism in 19 populations of the grasshopper Dichroplus pratensis Bruner in Argentina, spanning 22° of latitude and between sea level and >2,474-m altitude. Six characters were measured in 609 individuals (334 males and 275 females): total body, femur 3, tibia 3, tegmina and pronotum lengths, and pronotum height. Significant negative correlations between all six characters and latitude occurred. Correlations with altitude were weaker, although individuals at higher altitudes tended to be smaller, except at high latitudes. Extreme latitudes and altitudes correspond to the geographical and ecological margins of the species distribution and share comparable strenuous environmental conditions. Thus, this species follows the converse to Bergmann’s rule, that is, individuals tend to be smaller as the environment becomes cooler (when latitude or altitude are used as a proxy for temperature). When the six morphological characters where analyzed in both sexes with respect to mean January and July temperatures at each locality, positive (although not significant) correlations were obtained in all cases. Sexual dimorphism occurred throughout the geographic range involving not only differences in body size but also in body proportions, which can be explained through differential allometric growth and shorter developmental time in males (the species exhibits protandry). The latter can also explain the inversion of Rensch’s rule that occurs in D. pratensis: sexual size dimorphism decreases as general body size increases.

Field and laboratory studies investigated the preimaginal developmental time, adult emergence phenology, mating behavior, and weevil hosts of Necremnus tidius (Walker) (Hymenoptera: Eulophidae), a solitary ectoparasitoid of coleopteran larvae. In addition, changes in parasitism levels of the cabbage seedpod weevil, Ceutorhynchus obstrictus (Marsham) (Coleoptera: Curculionidae), by N. tidius were determined during 2003–2005 in commercial fields of canola (Brassica rapa L. and Brassica napus L.) in southern Alberta and Saskatchewan, Canada. Mean ± SE developmental time from egg to adult was 18.3 ± 0.23 d for specimens reared at 21°C and a photoperiod of 12:12 (L:D) h. Emergence began in late July in commercial fields near Lethbridge, AB, and 20 d later 81% of the population had emerged. Emergence was completed by the end of August. Mating was preceded by a complex courtship behavior with the male standing on the dorsum of the mesosoma and gaster of the female, flapping its wings without flight, leaning forward and stroking its antennae over the antennae of the female, leaning back, and repeating the sequence several times. The native weevil Ceutorhynchus neglectus Blatchley was determined to be an alternate host of N. tidius in central and northern Alberta. N. tidius was found in few commercial canola fields in 2003, but in 2004, it occurred over hundreds of thousands of hectares of canola cropland, reaching peak parasitism levels of 45%. In 2005, N. tidius was still common, but parasitism declined relative to that observed in 2004.

We examined the effects of host quality (as measured by gall size) and local mate competition (LMC) on the sex ratio of inquilines emerging from cynipid oak galls. In the galls of Trigonaspis sp. (Hymenoptera: Cynipidae), which were solitarily parasitized by the inquiline, the proportion of males decreased significantly with increasing gall size. Large galls produced large inquiline females and large numbers of offspring, but gall size did not affect mortality rate. In the galls of Cynipidae sp. 1 and sp. 2, which were parasitized by the inquilines either solitarily or gregariously, the overall sex ratio was female biased, and it did not change with increasing number of inquilines emerging from a single gall. Thus, in these galls, LMC is likely to have little effect on the sex ratio of the inquiline. The inquiline seems to manipulate its offspring sex ratio only in accordance with gall size.

Carabid beetles were pitfall-trapped in soybean, Glycine max (L.) Merr., fields hosting populations of soybean aphid, Aphis glycines Matsumura (Hemiptera: Aphididae), in central New York state in July and August 2004 and 2006. Carabids were collected from five fields located in three counties in 2004 and from two fields both located at the same farm in 2006. In total, adults of 60 carabid species were collected, 10 of which represent introductions from Europe. Agonum muelleri (Herbst), a Palearctic native, was the dominant carabid species both years, a role not previously reported in U.S. carabid assemblages. Both years, A. muelleri was the most abundantly trapped species, and it was collected in more than half of the pitfall traps. The majority of carabid individuals trapped, including A. muelleri, belonged to species overwintering as adults. The most common larval overwinterer, the European native Pterostichus melanarius (Illiger), made up only 6.0% (2004) and 5.5% (2006) of the total carabids species caught, yet this species was relatively broadly distributed (in 40.1% of traps in 2004 and 26.0% of traps in 2006). In three no-tillage fields with canopy closure, densities of the seven most common carabid species were high at the beginning of the season, but they decreased in early August as aphid densities began increasing. A significant negative exponential relationship described this relationship between activity density of carabids and aphid density. A no-choice feeding assay confirmed that the dominant species A. muelleri readily eats soybean aphids, which is consistent with carabid predation on soybean aphid populations. Pitfall traps were arrayed to allow comparisons of carabid beetle distributions among field edges, and distances 10 and 20 m into fields. Among the seven most common species, significantly more adults of A. muelleri, Poecilus chalcites (Say), Poecilus lucublandus (Say), and Pt. melanarius were trapped within fields compared with at field edges.

Interactions between ants and aphids range from mutualistic to antagonistic. Understanding the ecological basis for such interactions requires understanding the costs and benefits to the aphids of ant-tending. Such an analysis is not simple, because ants can simultaneously have positive and negative effects upon aphids. The aphids Pleotrichophorus utensis Pack & Knowlton and Uroleucon escalantii Knowlton (both Hemiptera: Aphididae) are occasionally tended by Formica obscuripes Forel (Hymenoptera: Formicidae) at field sites in central Colorado. To compare the relative effects of protection and predation by ants on aphid abundance, we experimentally crossed the presence of the ants and other predators on host plants on which one or both aphids occur. Within a week of the start of the experiment, ants had a strong negative impact on aphid numbers that lasted the course of the experiment. Nonant predators initially had a weak negative effect on aphids, but by the end of the experiment, the negative effect of nonant predators was similar in magnitude to the effect of the ants. The negative effect of ants and other enemies on aphids was nonadditive; simultaneous predation by ants and other enemies was not as strong as expected from estimates of predation rates by only ants or only other enemies. This study suggests that ants simultaneously protect and prey upon aphids. We suggest selection to appease ants and to gain protection from ants can both be important forces generating ant–aphid mutualisms.

Among social insects, individuals that grow or reproduce have different nutritional requirements than those that do not grow. Ants and termites have very different colony structure, and they should reveal differences in nutrient flow. Here, we show that the micronutrients calcium (Ca), copper (Cu), iron (Fe), potassium (K), magnesium (Mg), manganese (Mn), sodium (Na), and zinc (Zn) levels are different among castes in termite and ant colonies. In two separate experiments, colonies of the termite Reticulitermes flavipes (Kollar) (Isoptera: Rhinotermitidae) and the ant Myrmica punctiventris (Roger) (Hymenoptera: Formicidae) were divided into two equal-sized subunits. In both experiments, one subunit was fed an enriched diet containing Ca, Cu, Fe, K, Mg, Mn, Na, and Zn, whereas the other subunit was fed a control diet lacking these nutrients. In subunits fed the enriched diet, termite workers had higher levels of micronutrients than did soldiers, whereas ant workers had lower levels of micronutrients than did larvae. The only exceptions to this pattern were that Cu and Zn were found to be higher in termite soldiers, and Mn was found to be higher in ant workers. Our results suggest that micronutrients levels in both ants and termites match the nutritional requirements of different castes.

A liquid diet for rearing Ceratitis capitata (Wiedemann) (Diptera: Tephritidae) was developed. Several yeast-based products were evaluated as diet ingredients, and a combination of whole cell yeast (LBI2240) and hydrolyzed yeast (such as FNILS65) in 1:1–3:1 ratio was selected for use in the study. Larvae reared in a liquid diet with LBI2240:FNILS65 ratios of either 1:1 or 3:1 resulted in the same pupal recovery as to those reared in the conventional mill fee- based control diet. Larvae reared in a liquid diet with whole cell yeast only yielded the lowest pupal production, whereas other parameters such as adult emergence, adult fliers, pupal weight, egg production, and percentage of egg hatch were not affected. In diets fortified with vitamin-fortified yeast (RDA) or glutamine-rich yeast (GSH), there was no enhanced effect on insects, whereas some detrimental effects were observed in some of the parameters measured. A whole cell yeast to hydrolyzed yeast ratio of 3:1 was found to be the most suitable based on quality control parameters measured and cost-effectiveness. This is recommended for use in liquid diets targeting C. capitata mass rearing because the cost of whole cell yeast was 5 times cheaper than that of hydrolyzed yeast. This study also demonstrates that it is possible to rear C. capitata in a liquid diet at a similar cost to mill feed diet and still maintain the same fly quality as that from the conventional control diet.

Holymenia clavigera Herbst and Anisoscelis foliacea marginella Dallas (Hemiptera: Coreidae: Anisoscelini) use the same host plants (Passifloraceae), especially Passilfora suberosa L., and they have a very similar egg and nymphal morphology. This study compares the mouthparts of these coreids both intra- and interspecifically through scanning electron microscopy. Also, it determines the feeding sites for the fifth instars and for adults when offered some of their preferred structures (green fruit and mature leaves) of P. suberosa. Histological sections were performed on feeding sites, on plant pieces having the penetrated stylet in situ. Mouthpart morphologies were extremely similar between H. clavigera and A. foliacea marginella throughout ontogeny. The stylets reached the xylem, in almost all situations, followed by a low use of phloem. Nymphs and adults of both species consumed several fruit parts, including the seeds. When feeding upon the latter, endosperm and embryo were used for feeding. Feeding frequencies indicated that seeds are the main resource used by these coreids and that xylem feeding is probably related to water acquisition. Thus, H. clavigera and A. foliacea marginella are also extremely similar concerning use of host plant feeding sites and mouthpart morphology.

Approximately 197 species comprise the widespread syrphid tribe, the Cerioidini (Diptera: Syrphidae), but rearing data are known for <5% of species. We obtained puparia of 10 species from fieldwork in Costa Rica, Cuba, and México and from material loaned to us from Australia, Brazil, Costa Rica, and the United States. These species are included in four of the five genera recognized in the tribe: two species of Ceriana Rafinesque, 1815; three species of Monoceromyia Shannon, 1925; four of Polybiomyia Shannon, 1925; and one species of Sphiximorpha Rondani, 1850. We describe and compare these puparia. They all possessed the diagnostic characters for the tribe. However, no early stage characters were correlated, hence early stages did not form groups based on shared characters. Some structures were relatively constant in form such as head skeletons and locomotory organs, but characters that showed plasticity included integumental vestiture and respiratory organs. A few features such as the unusually broader than long posterior respiratory process of Ceriana ornata Saunders, 1845, the spicules on the dorsum of the prothorax of Sphiximorpha barbipes (Loew, 1853), and the mesothoracic hooks of Monoceromyia tricolor (Loew, 1861) were unique to these species. Most cerioidine larvae were reared from tree sap but others came from tree holes, the liquid center of a cut agave (Agavaceae) and bee nests (Hymenoptera, Apidae). Field observations of larvae and their breeding site suggested functional explanations for some morphological features.