A BSTR ACTThe plant Mentzelia pumila (family Loasaceae) has leaves and stems densely covered with tiny hooked trichomes. The structures entrap and kill insects and therefore are most probably protective. But they are also maladaptive in that they incapacitate a coccinellid beetle (Hippodamia convergens) that preys upon an aphid enemy (Macrosiphum mentzeliae) of the plant. The adaptive benefit provided by the trichomes is evidently offset by a cost.The leaves and stems of many plants are beset with small hairs, hooks, spines, or scales (1, 2). These epidermal elaborations, or trichomes, which can impart on a plant a characteristic pubescent appearance or abrasive ''feel,'' generally are believed to be defensive. Indeed, a number of insect herbivores, including aphids, leaf beetles, leafhoppers, and caterpillars, have been shown to be physically deterred by trichomes (2-5). In the course of field studies undertaken by two of us (T.E. and M.E.) in southern Arizona, we came across a plant, Mentzelia pumila (family Loasaceae), that seems to reap both benefit and harm from its possession of trichomes. It benefits because its trichomes are broadly incapacitating to insects, and it is harmed because among the insects incapacitated is a coccinellid beetle that preys on an aphid enemy of the plant.The observations we made are not nearly as extensive as we would have liked. They are presented here because we do not anticipate having future occasion to study the plant. Specifically, we provide a description of M. pumila's trichomes, and data on how these structures affect insects generally and a coccinellid beetle in particular. MATERIALS AND METHODSThe Plant (M. pumila). This plant is a multibranched herb, typically 30-60 cm in height, with lanceolate toothed leaves and yellow flowers (Fig. 1A). Its range extends from Wyoming southward to Texas, Arizona, and Mexico (6). Like other members of its genus, it bears a dense covering of tiny trichomes, which render its leaves and stems characteristically sandpaper-like to the touch. We made our observations in May 1991, on stands of the plant that we located in Cochise County, AZ, northward of Douglas, along highway U.S. 80 and in the environs of Portal.Microscopy. Fresh material was photographed with a Wild M400 photomicroscope. Items viewed with a scanning electronmicroscope (pieces of M. pumila leaves and stems; insects stuck to the plant) were prepared by being dehydrated in ethanol, critical-point dried, and gold-coated (7).Insects Found Entrapped on M. pumila. These were identified to species or genus where possible, otherwise mostly to family.The Aphid (Macrosiphum mentzeliae). Two species of aphid, M. mentzeliae and Pleotrichophorus wasatchii, have been reported from Mentzelia plants (8). We found only the former feeding on M. pumila at our study sites.The Coccinellid Beetle (Hippodamia convergens). This was by far the dominant coccinellid on M. pumila at our field sites. The species occurs throughout the United States (9).Tests with H. convergens. To obtain some measure...

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Semiochemical-based exotic species surveys targeting forest Coleoptera have gradually expanded in North America and elsewhere. Determining how various factors affect trap catches and increase species richness in traps is important for maximizing the efficacy of survey efforts. Studies were conducted in southern Maine and New Hampshire by using ethanol and alpha-pinene as lures to determine the influence of trap type, lure placement and size, and habitat type on catches of Scolytinae and Cerambycidae in coniferous forests. Three trap types (canopy malaise, intercept panel, and multiple-funnel), three lure placements/sizes (standard placement, above trap, and enlarged), and two habitat types (margins of clearcuts and shelterwood) were tested in three experiments. The three trap types performed equally well in terms of average number of species captured, but the canopy malaise caught more unique species than the other traps. In most cases, traps with lures placed above traps caught fewer beetles than lures hanging from the side of traps or with an expanded surface area. Generally, more insects were captured in shelterwood treatments versus the margins of clearcuts.

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Exotic insects are constantly intercepted at U.S. ports-of-entry. Of these, wood-boring beetles, particularly xyleborine ambrosia beetles, are sometimes missed during port inspections and become established in the United States. Euwallacea validus (Eichhoff) and Euwallacea interjectus (Blandford) are morphologically similar Asian ambrosia beetle species that vary by their fungal associates and their potential to cause economic damage. Euwallacea validus and E. interjectus were first discovered in New York (1975) and Hawaii (1976), respectively. Euwallacea validus was collected multiple times from widely separated localities and is assumed to have spread throughout the eastern United States. The discovery of E. interjectus in Florida (2011) and Texas (2011) prompted our review of the E. validus specimens because of the potential misidentification of the species. In addition, using mitochondrial cytochrome oxidase I (COI) DNA data and phylogenetic analysis, we tested the hypothesis that multiple introductions account for the U.S. populations of E. interjectus and E. validus. Our review of 7,184 specimens revealed an earlier introduction to the mainland for E. interjectus, which was first collected from Louisiana in 1984. This species is distributed in the South while E. validus occurs in the North with a known area of syntopy in northeastern Georgia. The extent of the syntopy within the United States is unknown and further investigation is required. Phylogenetic analysis of 24 E. interjectus and 20 E. validus individuals resolved clades that associated with each species and gross geographic provenance. Four well-supported clades represented E. interjectus which included the following localities: 1) Hawaii and Thailand; 2) Vietnam, Taiwan, and Texas; 3) Okinawa (Japan); and 4) Japan and several southern U.S. states. One clade comprised all E. validus specimens from Japan and the mainland United States. Four and two haplotypes were found for the E. interjectus and E. validus specimens, respectively, in mainland United States. Except for the Texas specimen, the haplotypes differed by one nucleotide. The relationship of the haplotypes and their sequence similarity suggested that the provenance of E. validus and the majority of E. interjectus haplotypes was Japan while the Texas haplotype originated later and from a location near Taiwan. Given the high nucleotide sequence difference between the Hawaiian and Thai haplotypes, the exact origin of the Hawaiian E. interjectus is unknown but likely Southeast Asia. A broader investigation including more SE Asian individuals will help to further explain the introduction of E. interjectus into Hawaii and Texas.

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Larvae of two insects, a coccinellid beetle (Hyperaspis trifurcata) and a chamaemyiid fly (Leucopis sp.), feed on cochineal insects and appropriate their prey's defensive chemical, carminic acid, for protective purposes of their own. H. trifurcata discharges the chemical with droplets of blood (hemolymph) that it emits when disturbed; Leucopis sp. ejects the compound with rectal fluid. Ants are thwarted by these defenses, which are compared with the previously-described defense of a pyralid caterpillar (Laetilia coccidivora) that disgorges carminic acid-laden crop fluid. The defensive fluid of all three larvae contains carminic acid at concentrations spanning a range (0.2-6.2%) proven deterrent to ants. Many insects are known to appropriate defensive substances from plants. Insects that acquire defensive chemicals from animal sources may be relatively rare.

In September of 2004, Sirex noctilio F. (Hymenoptera: Siricidae) was detected in New York State and later found to be established over a larger area, including parts of southeastern Canada and the northeastern United States. A key component of S. noctilio detection and management plans in other parts of the world where S. noctilio has become established are chemically girdled trap trees. Trap tree usage in North America is confounded by the presence of diverse communities of organisms that inhabit dead and dying trees. We trapped a portion of the arboreal insect community arriving at Pinus resinosa Ait. and Pinus sylvestris L., trap trees girdled 3 mo before (April), one month before (June), and at S. noctilio flight (July) in central New York. Multiple-funnel traps attached to trap trees captured 30,031 individuals from 109 species of Scolytinae, Cerambycidae, and Siricidae. Ips pini (Say) and Ips grandicollis (Eichhoff) accounted for almost 50% of the scolytines captured at trap trees and were present on all girdling dates. Significantly more scolytines and cerambycids were captured on P. sylvestris compared with P. resinosa, but species richness of captured insects did not differ between the two trees. More total and conifer-inhabiting scolytines and cerambycids were captured in traps on trees girdled in April and June and higher observed species richness was found on trees girdled in April and controls. Results from this study suggest a large community of arboreal insects and associated organisms are attracted to chemically girdled trap trees and likely interact with S. noctilio.