A New Genus of Cylindrical Bark Beetle (Coleoptera: Zopheridae: Colydiinae) in mid-Cretaceous Burmese Amber

A bizarre cylindrical bark beetle from mid-Cretaceous Burmese amber is described as Stegastochlidus saraemcheana, a new genus and species in the subfamily Colydiinae of the family Zopheridae. The male beetle is characterized by elongate protuberances covering its entire dorsal surface, a tarsal formula of 4-4-4 and ten-segmented antennae with the terminal segment expanded into a small club. The fossil is considered to have been a possible predator that lived among moss, lichens and fungi either attached to trees trunks or on the forest floor. A close association with fungi is indicated by strands of conidia attached to the cuticle of the beetle.

Colonization of weakened trees by mass-attacking bark beetles: no penalty for pioneers, scattered initial distributions and final regular patterns

Bark beetles use aggregation pheromones to promote group foraging, thus increasing the chances of an individual to find a host and, when relevant, to overwhelm the defences of healthy trees. When a male beetle finds a suitable host, it releases pheromones that attract potential mates as well as other ‘spying’ males, which result in aggregations on the new host. To date, most studies have been concerned with the use of aggregation pheromones by bark beetles to overcome the defences of living, well-protected trees. How insects behave when facing undefended or poorly defended hosts remains largely unknown. The spatio-temporal pattern of resource colonization by the European eight-toothed spruce bark beetle, Ips typographus , was quantified when weakly defended hosts (fallen trees) were attacked. In many of the replicates, colonization began with the insects rapidly scattering over the available surface and then randomly filling the gaps until a regular distribution was established, which resulted in a constant decrease in nearest-neighbour distances to a minimum below which attacks were not initiated. The scattered distribution of the first attacks suggested that the trees were only weakly defended. A minimal theoretical distance of 2.5 cm to the earlier settlers (corresponding to a density of 3.13 attacks dm −2 ) was calculated, but the attack density always remained lower, between 0.4 and 1.2 holes dm −2 , according to our observations.

Comparisons of traps and lures for monitoring grass grub Costelytra zealandica

Phenol the attractant pheromone of adult males of the native New Zealand grass grub Costelytra zealandica (White) is produced in the beetles as the result of bacterial degradation of tyrosine A lure consisting of a resin impregnated with phenol has been widely used to monitor male beetle flight activity The present formulation is highly attractive for the first week in the field but then loses activity rapidly A number of phenolcontaining formulations were tested to improve the lure A new formulation gave lower catches that were more stable with time producing data more suitable for population density estimation Phenylacetaldehyde a bacterial metabolite of phenylalanine was tested as a possible synergist to phenol Field results showed that this floral compound exhibited no behaviourallyactive properties to grass grubs when tested together with phenol Catches with water traps were compared with those in sticky delta and flat delta traps in two vineyards and in pasture Water traps caught four times more beetles

RESPONSES OF CONOPHTHORUS SPP. (COLEOPTERA: SCOLYTIDAE) TO BEHAVIORAL CHEMICALS IN FIELD TRIALS: A TRANSCONTINENTAL PERSPECTIVE

We tested six behavioral chemicals, pityol, conophthorin, 4-allylanisole, verbenone, 2-hexenol, and α-pinene, in a series of field trials directed at six combinations of Conophthorus Hopkins – Pinus L. spp. (Pinaceae) in sites distributed across North America. Beetle – host tree combinations included Conophthorus ponderosae Hopkins on Pinus ponderosa Laws., C. ponderosae on Pinus monticola Dougl., Conophthorus conicolens Wood on Pinus pseudostrobus Lindl., Conophthorus teocotum Wood on Pinus teocote Schl. & Cham., Conophthorus coniperda (Schwarz) on Pinus strobus L., and Conophthorus resinosae Hopkins on Pinus resinosa Ait. trans-Verbenol was tested only on C. resinosae on P. resinosa. Traps baited with pityol caught more beetles than unbaited traps in nearly all of the assays, and conophthorin consistently inhibited male beetle response to pityol for all species tested. Behavioral responses of species of Conophthorus to α-pinene appeared to parallel host phylogeny, inasmuch as beetles using Haploxylon pines as hosts utilized α-pinene as a synergist for the beetle-produced pityol, whereas beetles using Diploxylon pines as hosts did not. α-Pinene was a synergist for pityol in C. ponderosae on P. monticola and C. coniperda on P. strobus, but not for species of Conophthorus on any other pines tested. Conophthorus ponderosae on P. ponderosa was the only beetle–host combination tested where verbenone was a synergist for pityol, but this effect was not consistent in all years of testing. It was also the only beetle–host combination in which 4-allylanisole was a repellent. For all other beetle–host combinations, verbenone was neutral to slightly repellent and 4-allylanisole was either synergistic or neutral in pityol-baited traps. Promising synergists and interruptants/repellents were identified for implementation in pest-management regimes, including conophthorin as an interruptant for all species of Conophthorus tested, 4-allylanisole as an interruptant for C. ponderosae on P. ponderosa, α-pinene as a synergist for pityol in all species tested on Haploxylon pines, and 4-allylanisole as a synergist for pityol in C. conicolens and C. coniperda.

EVIDENCE FOR AN AIRBORNE SEX PHEROMONE IN THE COLORADO POTATO BEETLE, LEPTINOTARSA DECEMLINEATA

Trials using four different sex combinations of Colorado potato beetle, Leptinotarsa decemlineata Say, demonstrated that male beetles move upwind towards females, whereas no attraction was seen between any of the other combinations. Attraction was not found to increase significantly after the female reached 10 days old. Visual stimuli appear to be unimportant from a distance of 50 cm. Orientation behaviour by the male beetle was observed as it walked upwind towards the female; no identifiable calling behaviour by the female was observed. The data indicate a sex pheromone is being produced by the female and is used by the male for mate location from a distance.

Oryctonema genitalis gen. et sp. nov., (Rhabditidae; Nematoda) from the Genital System of Oryctes monoceros Ol. (Scarabaeidae: Coleoptera) in West Africa

A new nematode, Oryctonema genitalis gen. et sp. nov., which possesses features of both the Rhabditidae and Angiostomatidae, is described from the genital system of the dynastid beetle, Oryctes monoceros O1. in West Africa. Multiplication of O. genitalis occurs in the bursa copulatrix of female beetles and the nematodes sustain themselves for long periods in the numerous aedaegal ducts of the male beetle. The possible influence of these nematodes on host viability is discussed.

The Columbian Timber Beetle, Corthylus columbianus (Coleoptera: Scolytidae): V. A Description of the Mycetangia

The mycetangia of Corthylus columbianus Hopkins are described. These structures lay immediately below the integument of the pronotum, one in each ventrolateral region. Each mycetangium is a coiled tube 4.69 ± 0.35 mm. in length, cream colored, opening into the anterior coxal cavity. Mycetangia occur only in the male beetle and provide the overwintering storage site and transmission mechanism for associated microorganisms. Smears and cultures of the mycetangia were positive for ascospores and vegetative cells of a yeast, Pichia sp., which coincides with the microsymbiote dominant in developmental chambers of the larvae.

The Morphology and Functions of the Reproductive Systems of Dendroctonus monticolae Hopk. (Coleoptera: Scolytidae)

The male and female reproductive organs of the mountain pine beetle, Dendroctonus monticolae Hopk. are described, and interpretations given for functions of the parts on the basis of activity during mating, sperm transfer, egg formation and ovulation. Some morphological changes of the reproductive organs during the adult life cycle are also noted.Three pairs of accessory glands associated with spermatophore production are evident in the male beetle. One of these was previously termed the seminal vesicles. A complex musculature operates the male genital organ during copulation. The female organs have four telotrophic ovarioles with a posterior calyx region that has a possible secretory function. Evidence indicates that organs previously termed "colleterial glands" have a digestive and reabsorbing function. The bursa copulatrix may be more closely allied with the function of the accessory glands than with the mating process. Parts of the spermatheca have been more precisely defined according to function.