J. H. Frank

Insects and allies associated with bromeliads: a review.

Bromeliads are a Neotropical plant family (Bromeliaceae) with about 2,900 described species. They vary considerably in architecture. Many impound water in their inner leaf axils to form phytotelmata (plant pools), providing habitat for terrestrial arthropods with aquatic larvae, while their outer axils provide terraria for an assemblage of fully terrestrial arthropods. Many bromeliads are epiphytic.Dominant terrestrial arthropods with aquatic larvae inhabiting bromeliad phytotelmata are typically larvae of Diptera, of which at least 16 families have been reported, but in some circumstances are Coleoptera, of which only three families have been reported. Other groups include crabs and the insect orders Odonata, Plecoptera, and Trichoptera, plus Hemiptera with adults active on the water surface. The hundreds of arthropod species are detritivores or predators and do not harm their host plants. Many of them are specialists to this habitat.Terrestrial arthropods with terrestrial larvae inhabiting bromeliad terraria include many more arachnid and insect orders, but relatively few specialists to this habitat. They, too, are detritivores or predators.Arthropod herbivores, especially Curculionidae (Coleoptera) and Lepidoptera, consume leaves, stems, flowers, pollen, and roots of bromeliads. Some herbivores consume nectar, and some of these and other arthropods provide pollination and even seed-dispersal.Ants have complex relationships with bromeliads, a few being herbivores, some guarding the plants from herbivory, and some merely nesting in bromeliad terraria. A few serve as food for carnivorous bromeliads, which also consume other terrestrial insects.Bromeliads are visited by far more species of arthropods than breed in them. This is especially notable during dry seasons, when bromeliads provide moist refugia.

Survival, development and predatory effects of mosquito larvae in Venezuelan phytotelmata

To assess the influence of microhabitat and season on predator growth and sur- vival and prey community structure, first instars of native Toxorhynchites haemorrhoidalis, a predatory mosquito, were released into Heliconia bracts, bamboo internodes, and the axils of two species of Aechmea bromeliads during wet and dry seasons in a lowland rain forest in eastern Venezuela. Experimental and control microhabitats were compared by complete censusing of macroscopic invertebrates 10 and 20 days after releases. Survival of T. haemorrhoidalis differed significantly among habitats and was reduced by desiccation in dry-season bamboos and in Aechmea nudicaulis and by the presence of a preda- tory damselfly (Odonata: Zygoptera) in bromeliads. Developmental rate differed among habi- tats in the wet but not in the dry season; rapid wet-season maturation was associated with increased prey abundance in Heliconia. Larvae of T. haemorrhoidalis consumed particular taxa and size categories of dipterous prey. Predation significantly reduced the abundance and skewed size-class distributions of Culicidae, Ceratopogonidae, Psychodidae, and pooled samples of Thaumaleidae plus Chirono- midae. In bamboos, instar distributions of other mosquitoes were skewed in the presence of T. haemorrhoidalis even though a significant reduction in mosquito abundance was not detec- ted. A decrease in species richness of aquatic Diptera was associated with intense predation by Toxorhynchites in Heliconia and A. nudicaulis. Toxorhynchites theobaldi was recognized as the naturally occurring predator in local bamboos, and released larvae caused significant reductions in abundance or size-class frequency shifts among three families of Diptera. Niche segregation between these sympatric Toxorhynch- ites is maintained by oviposition preferences: the larger species, T. theobaldi, oviposits in bamboos and the smaller T. haemorrhoidalis occurs in plant bracts and axils.

HOW RISKY IS BIOLOGICAL CONTROL? COMMENT

Caley, M. J., and D. Schluter. 1997. The relationship between local and regional diversity. Ecology 78:70-80. Cornell, H. V. 1985a. Local and regional richness of cynipine gall wasps on California oaks. Ecology 66:1247-1260. . 1985b. Species assemblages of cynipine gall wasps are not saturated. American Naturalist 126:565-569. Westoby, M. 1985. Two main relationships among the components of species richness. Proceedings of the Ecological Society of Australia 14:103-107. * 1993. Biodiversity in Australia compared with other continents. Pages 170-177 in R. E. Ricklefs and D. Schluter, editors. Species diversity in ecological communities: historical and geographical perspectives. University of Chicago Press, Chicago, Illinois, USA. . 1998. The relationship between local and regional diversity: comment. Ecology 79:1825-1827.

Integrated Pest Management of Pest Mole Crickets with Emphasis on the Southeastern USA

There are at least 70 species of mole crickets (Orthoptera: Gryllotalpidae). Some are rare, others are innocuous, and a few are important pests. These soil-dwelling pests damage underground parts of a long list of cultivated plants. Although tillage and flooding are used successfully in some situations to bring these pests to the soil surface and expose them to vertebrate and other predators, chemical pesticides are widely used against them. Knowledge of their life history is used to time application of chemical treatments to save money, but is not used as widely as it might be. Classical biological control has been used against immigrant mole crickets in Hawaii, Puerto Rico, and the southern USA. In Florida, three Scapteriscus species from South America cause major damage to pastures and turf and are targets of a classical biological control program. Population levels of two of the pest species have been reduced substantially in Florida by establishment of a tachinid fly (Ormia depleta) and a steinernematid nematode (Steinernema scapterisci) from South America. The nematode also functions as a biopesticide. Managers of pastures and turf in Florida have thus far derived benefit from these classical biological control agents without understanding their function: use of chemicals is reduced when mole cricket populations are lower due to action of these organisms. Future enhancement of the action of O. depleta and of a sphecid wasp (Larra bicolor, which also was introduced from South America) probably will demand deliberate planting of nectar sources for adults of these biological control agents, and the advantage will be to managers who adopt such a strategy. Chemical pesticide use is strongly promoted by a large chemical industry, whereas biopesticidal use has thus far been little promoted and sales have been few. Even managers who do not change their simple strategy of pesticide use in response to damage by mole crickets, and have no knowledge of the differing life cycles of the three Scapteriscus species or of the presence and action of the classical biological control agents, will derive benefit as these biological control agents (and a predatory beetle which has not yet been released) increase their distribution.

Coastal Staphylinidae (Coleoptera): A worldwide checklist, biogeography and natural history

Abstract We provide a list of the 392 described species of Staphylinidae confined to coastal habitats worldwide. The list is in taxonomic sequence by subfamily, tribe, and genus and includes 91 genera. We provide the page reference of the original description of every species and genus listed and of many synonyms. We note the existence of recent reviews, phylogenies and keys of each of the tribes and genera included. Coastal Staphylinidae contain eight subfamilies: Microsilphinae, Omaliinae, Pselaphinae, Aleocharinae, Oxytelinae, Scydmaeninae, Paederinae, and Staphylininae. By ‘coastal habitats’ we mean habitats existing on the sea coast and subject to inundation or at least splashing by the very highest tides. This includes rocky, boulder, coral, sandy, and muddy seashores, and at least portions of salt-marshes, estuaries, and mangrove swamps. We exclude the sand dune habitat and higher parts of sea-cliffs. The list notes distribution of all the species, first according to the ocean or sea on whose shores it has been recorded, and second by country (and for the larger countries by province or state). Although this distribution is undoubtedly incomplete, it provides a basis for future development of a dedicated database. The ‘Habitats, Habits, and Classificatory Notes’ section is designed to provide ecologists with further taxonomic and ecological information. It includes references to descriptions of the immature stages, behavior of adults and immatures, their food, natural enemies, and habitat. We would have preferred to separate these entities, but current knowledge of ecology is developed in few instances beyond natural history. The Pacific Ocean basin was the origin and contributed to the dispersal of the majority of specialist coastal Staphylinidae at the level of genus. However, at the level of species, species belonging to non-coastal-specialist genera are about as likely to occur on the shores of other oceans as on the shores of the Pacific. This difference is a reflection of the antiquity of coastal genera and species. A complete bibliography, and habitat and habitus photographs of some representative coastal Staphylinidae species are provided.

Introduction to the behavioral ecology of immigration. The immigration of insects to Florida, with a tabulation of records published since 1970.

A table is presented of the recent (published since 1970) records of presence of exotic insects in Florida. The table includes 271 species, 209 of which were first collected in Florida after 1970. We assumed that these insects are immigrants, and we calculated mean rates of 7.7 and 12.0 immigrations per year in the 1970s and 1980s, respectively. We judge that about 20 recent immigrants are, or could become, major pests in Florida. At least 8% of the species appear to have arrived as stowaways, and many of the actual or potential major pests are among them. Immigrant species are not equitably distributed among orders or among families within orders. Species in the orders Lepidoptera and Coleoptera are especially well-represented. By far the largest proportion of recent insect immigrants to Florida comes from the Neotropical region. Our results suggest further information that is needed to answer questions about the invasibility of Florida.

Precinctive Insect Species in Florida

The number of insect species now occurring in Florida is estimated at about 12,500. Statements from specialists in 28 insect taxa (at the level of family or higher), representing some 40% of the fauna, suggest that about 12% of the total fauna (13% of the indigenous fauna, with range 0-43% among taxa) is precinctive. Immigrants form less than 8% of the total fauna. Only 42 (0.3%) species are known to have been introduced deliberately, for purposes of biological control. The proportions of immigrants and of precinctive species are far lower than in the Hawaiian insect fauna, but the proportion of immigrants exceeds that of the fauna of the contiguous United States as a whole.

Potential Biodiversity Loss in Florida Bromeliad Phytotelmata due to Metamasius callizona (Coleoptera: Dryophthoridae), an Invasive Species

Abstract An annotated list of the aquatic invertebrates inhabiting water impounded in the leaf axils of Florida’s native epiphytic bromeliads is provided. Of the 22 species reported, 9 are yet undescribed. Of the 13 described species, 10 are believed to be native. Five of the native species and perhaps all of the undescribed species are precinctive (“endemic”). These invertebrate animals and their bromeliad host plants are at risk of extinction due to destruction of the host plants by Metamasius callizona (Chevrolat) (Coleoptera: Dryophthoridae), an invasive weevil.

Development of Metamasius callizona (Coleoptera: Curculionidae) on pineapple stems

In the laboratory at 26°C and 14:10 L:D, female Metamasius callizona (Chevrolat) oviposited in pocket-shaped slits that they cut in pineapple leaves. Eggs were 1.98 × 0.97 mm and incubation averaged 8.3 d at 82% RH. On a diet of pineapple stem, 5 larval instars averaged 37.4 d to develop to the pupa. The pupal stage averaged 11.8 d, and the pupal weight averaged 0.12 g. Development from oviposition to adult emergence took about 8 wk.

Introduction to the Behavioral Ecology of Introduction. The Introduction of Insects into Florida

About 351 insect species have been introduced into Florida for potential release since 1890, though many were never released. Published and unpublished records show that 154 were released, almost all of them (151) as biological control agents of insect pests and weeds. An estimated 24.5% and 66.7% of the species released against insect pests and weeds, respectively, established populations in Florida. The proportion of insect predators (26.7%) was very similar to that of insect parasitoids (23.9%) established. Insect pests targeted were mainly Homoptera (48%), Lepidoptera (24%), and Coleoptera (10%). Most of the insect pests (79%) and weeds (75%) targeted are not native to Florida; 43% of the insect pests are native to Asia, and 50% of the weeds are native to South America. None of the native insect pests and weeds targeted occurs only in Florida. There was no clear relationship of the number of individuals released, nor of their geographic origin, nor of the county in which they were released, to the probability of establishment.