Interdomain symbioses with bacteria allow insects to take advantage of underutilized niches and provide the foundation for their evolutionary success in neotropical ecosystems. The gut microbiota of 13 micro-allopatric tropical pentatomid species, from a Costa Rican lowland rainforest, was characterized and compared with insect and host plant phylogenies. Like other families within the Pentatomomorpha, these insects (within seven genera—Antiteuchus, Arvelius, Edessa, Euschistus, Loxa, Mormidea, and Sibaria) house near-monocultures of gamma-proteobacteria in midgut crypts, comprising three distinct lineages within the family Enterobacteriaceae. Identity of the dominant bacteria (78–100% of the recovered 16S rRNA genes) was partially congruent with insect phylogeny, at the level of subfamily and tribe, with bacteria closely related to Erwinia observed in six species of the subfamily Pentatominae, and bacteria in a novel clade of Enterobacteriaceae for seven species within the subfamilies Edessinae and Discocephalinae. Symbiont replacement (i.e., bacterial “contamination” from the environment) may occur during maternal transmission by smearing of bacteria onto the egg surfaces during oviposition. This transmission strategy was experimentally confirmed for Sibaria englemani, and suspected for four species from two subfamilies, based on observation of egg probing by nymphs. Symbiont-deprived S. englemani, acquired via egg surface sterilization, exhibited significantly extended second instars (9.1 days compared with 7.9 days for symbiotic nymphs; p = 0.0001, Wilcoxon's rank with Bonferroni correction), slower linearized growth rates (p = 0.005, Welch 2-sample t-test), and qualitative differences in ceca morphology, including increased translucency of crypts, elongation of extracellular cavities, and distribution of symbionts, compared to symbiotic nymphs. Combined, these results suggest a role of the symbiont in host development, the reliable transference of symbionts via egg surfaces, and a suggestion of co-evolution between symbiont and tropical pentatomid host insects.

The Pentatomidae, representing the fourth largest family within Heteroptera, are one of the most diverse groups with about 800 genera and more than 4,700 species in the world. In the Neotropics, about 230 genera and 1,400 species are included in seven subfamilies of the world's nine subfamilies; four subfamilies are exclusively of the Neotropics. In this chapter, for each subfamily, a diagnosis, an overview of the classifi cation, and information on life history, ecology, and economic importance are given. Comprehensive keys and diagnosis to the subfamilies, tribes, and genera for the Neotropical Region, including Mexico, Central and South America, and the West Indies, are also given.

Heteroptera is the most numerous and diverse suborder of Hemiptera, with about 38,000 species. This diversity also involves cytogenetic features, including chromosome number and a sex determining system. Information about heterochromatin occurrence and distribution is scarce in heteropterans, but still, there is some evidence of variability. We determined the chromosome number and CMA₃/DAPI-banding pattern of 179 individuals of 25 heteropteran species from Brazil. Eight species of Pentatomidae exhibited a constant chromosome number (2n = 12 + XY), but in Coreidae (12 species), Largidae (1 species), Rhopalidae (1 species), and Pyrrhocoridae (3 species), the numbers ranged from 2n = 10 + 2m + X0 to 2n = 24 + 2m + X0. Although there were no large differences in the chromosome size between species, the CMA₃/DAPI-banding patterns differed markedly. Among the genera, species of Edessa, Spartocera, Hypselonotus, Phtia,Holhymenia and Euryophthalmus showed a large accumulation of heterochromatin, while the other species exhibited few or no heterochromatic bands. In general, when heterochromatin was more accumulated, this occurred preferentially at terminal positions, except in Holhymenia histrio, which exhibited intercalary bands. This study made it possible to identify some chromosome rearrangements and to enhance our knowledge of the evolutionary mechanisms that determine karyotype differentiation in Heteroptera.

Previous chromosome mapping of multigene families in Pentatomomorpha (Heteroptera) insects, which was restricted to the major rDNA, revealed remarkable conservation of number of clusters and chromosomal positions. Aiming to understand the chromosomal organization and evolutionary patterns of multigene families in karyotypes of Heteroptera, we performed a chromosomal mapping using four distinct multigene families in representatives of Coreidae (ten species) and Pentatomidae (five species). A single pair of the major rDNA cluster (18S rDNA probe) and a single pair of the minor rDNA cluster (5S rDNA probe), both terminally located were primarily observed, being, in most species, located in distinct chromosomes. However, some alternative patterns were also observed. In species in which the U2 snDNA and H4 gene clusters were mapped, they were mainly located in one autosomal pair each, wherein the H4 gene cluster was located in different positions. Our data suggest that the karyotype diversity reported in Coreidae is not reflected in the distribution diversity of multigene families. This contrasts with the data for Pentatomidae, with a conserved gross karyotype but a discrete diversity in the location of the clusters of multigene families, indicating genome dynamics for these markers. The findings are discussed to shed light on the possible causes for the conservation or variation observed and to assist in understanding the chromosomal evolutionary trends in the group.

The family Coreidae is distributed worldwide, but these phytophagous bugs are most abundant in the tropics and subtropics. In the Neotropical region, all of the subfamilies and 16 tribes are represented. In tropical ecosystems, these bugs feed on herbs and shrubs in open areas of forests as well as at the forest edge. Some species are spectacularly colored, and unusual expansions of antennae, humeral angles, femora, or tibiae occur in many groups. Some of them move lazily even when disturbed and hardly fl y to escape; others are extremely nimble, fast fl ying away when disturbed. They are frequently encountered in crops, representing important pests in several commodities. No one common name is universally accepted for the family, and none of the frequently used names (e.g., squash bug, leatherbug, leaf-footed bug, Randwanzen) are collectively appropriate for all members of the family.