James K. Liebherr

Flightlessness in insects.

The evolution of wings is heralded as the most important event in the diversification of insects, yet flight-wing loss has occurred in nearly all pterygote insect orders. Flight loss is especially prevalent among taxa inhabiting historically stable habitats. Recent studies of wing-polymorphic species have revealed numerous selective trade-offs in the reproductive potentials of winged versus flightless forms. A diverse set of environmental factors, both biotic and abiotic, trigger flight loss in alary polyphenic taxa, presumably by influencing juvenile hormone titers. Phylogenetic comparisons promise to elucidate much about the historical contexts and consequences of flight loss.

GENE FLOW IN GROUND BEETLES (COLEOPTERA: CARABIDAE) OF DIFFERING HABITAT PREFERENCE AND FLIGHT-WING DEVELOPMENT

Estimates of gene flow vary 100‐fold among five carabid species, ranging from the winged lowland subtropical Agonum elongatulum to the flightless montane temperate Platynus angustatus. Results based on Wrights (1943) FST method, and Slatkins (1981) graphical and (1985a) private‐allele methods are concordant. Genetic heterogeneity, measured by Wrights FST, is not correlated with degree of flight‐wing development; one fully winged species exhibits heterogeneity of the same order as a vestigially winged species. Genetic heterogeneity is positively correlated with the average elevation of collection sites for these species. Lower levels of gene flow associated with greater genetic subdivision may occur in upland areas because of habitat fragmentation (due to topographic diversity) and habitat persistence (leading to a lower extinction rate for populations). In at least one species, the distribution of stable infraspecific polymorphisms indicates that the high estimate of present‐day gene flow is likely to be due to historical gene flow and not to present‐day conditions.

Cladistic analysis, phylogeny and biogeography of the Hawaiian Platynini (Coleoptera: Carabidae)

The 128 known native Hawaiian species of the tribe Platynini are analysed cladistically. Cladistic analysis is based on 206 unit‐coded morphological characters, and also includes forty‐one outgroup taxa from around the Pacific Rim. Strict consensus of the multiple equally parsimonious cladograms supports the monophyly of the entire species swarm. The closest outgroup appears to be the south‐east Asian‐Pacific genus Lorostema Motschulsky, whose species are distributed from India and Sri Lanka to Tahiti, supporting derivation of the Hawaiian platynines from a source in the western or south‐western Pacific. The biogeographic relationships of the Hawaiian taxa are analysed using tree mapping, wherein items of error are minimized. The area cladogram found to be most congruent with the phylogenetic relationships, and most defensible based on underlying character data is {Kauai[Oahu(Hawaii{Lanai[East Maui(West Maui + Molokai)]})]}. This progressive vicariant pattern incorporates progressive colonization from Kauai, and vicariance of the former Maui Nui into the present islands of Molokai, Lanai, West Maui and East Maui. The evolution of flightlessness, tarsal structure, pronotal setation and bursal asymmetry are evaluated in the context of the cladogram. Brachyptery is a derived condition for which reversal is not mandated by the cladogram, although repeated evolution of reduced flight wings is required. Tarsal structure supports Sharps (1903) recognition of Division 1 as a monophyletic assemblage, but exposes his Division 2 as a paraphyletic group requiring removal of the genus Colpocaccus Sharp. Pronotal setation is exceedingly homoplastic, and is not useful for delimiting natural groups. Left‐right asymmetry of the bursa copulatrix reversed twice independently, resulting in mirror‐image bursal configurations in B. rupicola and Prodisenochus terebratus of East Maui. The amount of character divergence is greater among species comprising Division 1 than among species of its sister group, the redefined Division 2. Based on superior fit of Division 1 relationships to the general biogeographic pattern, a greater speciation rate coupled with more extensive extinction is rejected as the cause for this greater divergence. Intrinsic differentiation in the processes underlying cuticular evolution appears to be more consistent with the observed biogeographic and morphological patterns.

Distribution and Abundance of Carabidae (Coleoptera) Associated with Soybean Aphid (Hemiptera: Aphididae) Populations in Central New York

Abstract 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.

Risk of Infection by the Fungal Pathogen Entomophaga maimaiga Among Lepidoptera on the Forest Floor

Abstract The entomopathogenic fungus Entomophaga maimaiga causes epizootics in gypsy moth, Lymantria dispar (L.), populations and persists in forests as a reservoir of spores in soil at the bases of trees. To investigate whether E. maimaiga infects Lepidoptera living in leaf litter, we collected and reared larvae in leaf litter, understory vegetation, and on tree boles within a 200-cm radius around trunks of red oak, Quercus rubra L., trees. Among the 358 lepidopteran larvae reared, only one gelechiid larva (out of 84 collected) and one larva of the noctuid Sunira bicolorago (out of 20 individuals from this species) were infected by E. maimaiga. Our collections included 67 gypsy moth larvae, of which 25 (37%) were infected by E. maimaiga. The majority of infected gypsy moth larvae were collected during the second half of June, when few nontarget Lepidoptera were present in the oak leaf litter. A bioassay of Zanclognatha laevigata Grote, a herminiine noctuid whose larvae spend their entire lives in leaf litter, yielded no infection. Because laboratory host specificity studies had demonstrated high levels of infection only in lymantriid larvae, we also caged larvae of the lymantriid Orgyia leucostigma (J. E. Smith) over soil at the bases of trees or in understory vegetation. Levels of infection for O. leucostigma remained consistently lower than among caged gypsy moth larvae, and infection was always higher in the soil than on the understory vegetation. We conclude that, aside from gypsy moth larvae, E. maimaiga infections among litter-dwelling lepidopteran larvae were rare, and we hypothesize that infection of other lymantriids in the field will depend on whether they visit the ground level for a significant period of time.

Use of RAPD analysis to trace the origin of the weevil pathogen Zoophthora phytonomi in North America.

In North America, the fungal pathogen Zoophthora phytonomi has been known to cause significant levels of infection in introduced clover leaf weevil populations, Hypera punctata , since 1885. This pathogen was never noted in introduced populations of alfalfa weevil, H. postica , sympatric with clover leaf weevil until 1973 when it was found in alfalfa weevil in Ontario. From 1973 through 1981, Z. phytonomi was progressively found further south from Ontario. Whether these reports of Z. phytonomi infecting H. postica actually demonstrate spread by a novel genotype has previously been proposed and disputed. PCR-RAPD analysis was used to compare isolates of Z. phytonomi from both hosts in North America, and from H. postica in Israel with Z. radicans and Conidiobolus osmodes as outgroups. Both phenetic and cladistic analyses demonstrate that two main genotypes of Z. phytonomi occur in North America; one genotype including only H. punctata isolates with a second more homogeneous and principally including isolates from H. postica . The genotype principally including isolates from H. postica was more closely related to isolates from H. postica in Israel than to the other North American group, but also included one isolate from H. punctata . Based on affinity with Israeli genotypes, this latter strain may have originated in the Eurasian areas where H. postica is endemic. The degree of host specificity of these two North American genotypes of Z. phytonomi will require further investigation.

Ovoviviparity in carabid beetles of the genus Pseudomorpha (Insecta: Coleoptera)

Ovoviviparity is reported for the first time in the ground beetle family Carabidae. Eclosed larvae and fully developed embryos are found within the expanded lateral oviducts, bursa copulatrix and vagina of the putative myrmecophiles Pseudomorpha angustata and P. hubbardi. Eclosed larvae do not appear to be active while held inside the female prior to larviposition. Maximum larval numbers occur from mid-July to early September in these Arizona species, implying that larviposition is timed to coincide with summer rains. Larviposition is hypothesized as a means to eliminate egg mortality due to predation by ant hosts.

Unfortunate encounters? Novel interactions of native Mecyclothorax, alien Trechus obtusus (Coleoptera: Carabidae), and Argentine ant (Linepithema humile, Hymenoptera: Formicidae) across a Hawaiian landscape

The Hawaiian Islands support a speciose radiation of native Mecyclothorax beetles (Coleoptera: Carabidae). This lineage has undergone a classical island radiation resulting in extensive ecological specialization, flight-wing loss, and 100% single-island endemism. We report on the sympatric occurrence of several Mecyclothorax species endemic to Haleakala volcano, East Maui with the newly arrived, adventive Trechus obtusus (Coleoptera: Carabidae), a tramp species originally from Europe. Arrival of T. obtusus in afforested, non-native gymnosperm plantation forest near Polipoli, Maui was associated with subsequent decreased abundance of native Mecyclothorax beetles. Since discovery of T. obtusus on Haleakala, their populations have been transformed through subsequent increase in frequency of brachypterous individuals. Consequences of this transformation to flight-wing dimorphic populations may simultaneously include enhanced reproductive capacity of brachypterous individuals, increased local adaptation of populations, and enhanced metapopulational dynamics ultimately permitting range expansion and occupation far beyond anything observed for the monomorphically brachypterous native Mecyclothorax. Trechus obtusus and several Mecyclothorax species occur sympatrically with Argentine ant, Linepithema humile (Hymenoptera: Formicidae) in subalpine shrublands on Haleakala. Recent sampling corroborates earlier findings that localized presence of Argentine ant is associated with significantly decreased abundance of native Mecyclothorax. Conversely, abundance of the continental T. obtusus is not significantly affected by ant presence.

Blackburnia lata sp. n. (Coleoptera: Carabidae) from Kauai: morphological transformation in the arboreal microhabitat

Blackburnia lata sp. n. is described from the western reaches of the Alakai Swamp Trail, Kauaikinana Stream watershed, Kauai. Blackburnia lata is placed phylogenetically among other Kauai species in the subgenus Blackburnia Sharp, 1878. It is sympatric with three closely related species, all distributed largely within the limits of the primeval Kauai caldera, but allopatric with its adelphotaxon, B. atra Liebherr, found on Mt. Kahili, an isolated southern spur of the Mt. Waialeale massif. All five species occur in arboreal mossmats, at the same time exhibiting substantial variation in tarsal configuration. Tarsal evolution across this mossmat-specific lineage suggests that a single tarsal conformation is not required for occupation of this arboreal ecological zone. Historical transformation patterns of tarsal characters are not entirely congruent with the phylogenetic relationships among these species, and inclusion or exclusion of these characters in cladistic analysis is irrelevant to the definition of phylogenetic relationships. This incongruence argues against the necessity of excluding characters from phylogenetic analysis because they are deemed adaptive, while supporting the total evidence approach, wherein all potential synapomorphies are analyzed simultaneously to estimate phylogeny, regardless of their putative adaptive significance.

Blackburnia gastrellariformis sp. n. (Coleoptera: Carabidae), from Molokai: successful prediction of a new taxon by reconciled tree analysis

Blackburnia gastrellariformis sp. n., is described from East Molokai, Hawaii. Based on cladistic parsimony analysis of adult characters, the species is hypothesized to be most closely related to B. komohana Liebherr & Zimmerman of West Maui, with these two species comprising the adelphotaxon to the East Maui species pair, B. haleakala Liebherr & Zimmerman + B. putealis (Blackburn). Previous reconciled tree analysis for the Hawaiian Blackburnia radiation conducted before discovery of B. gastrellariformis found a general pattern in which Molokai and West Maui were hypothesized as sister-areas to the exclusion of the East Maui volcano, Haleakala, though the less common, incongruent area relationship of (Molokai (West Maui + East Maui) was also represented in the taxon-area cladogram. In the present reconciled tree analysis, the closest hypothesized relationship of B. gastrellariformis and a West Maui species corroborates the more common pattern by replacing items of error in the previous analysis with the newly discovered species. Elevational habitat shifts are invoked to explain the occurrence of numerous sister-species pairs in Molokai and West Maui, currently separated by the Pailolo Channel, relative to species occupying Haleakala.