Genetic variation in foraging traits among inbred lines of a predatory mite.

Response of predators to herbivore-induced plant volatiles can affect the length of time a predator spends in a prey patch and the probability of a predator finding a new prey patch. Variation in response to herbivore-induced plant volatiles may lead to different foraging decisions among individuals, thereby affecting both within-patch dynamics and between-patch dispersal. We found significant phenotypic and additive genetic variation in two behavioral assays of response to herbivore-induced plant volatiles among inbred isofemale lines of the predatory mite, Phytoseiulus persimilis. In wind-tunnel tests to measure patch residence time, adult female predators from certain lines left prey patches sooner than others when a distant source of herbivore-induced plant volatiles was presented; whereas such variation disappeared when no distant volatiles were presented. In a measure of patch location, certain lines were more likely than others to locate a prey-infested leaf disc; again there was no difference when uninfested leaf discs were used. Patch location was negatively correlated with patch residence. That is, lines that were more likely to leave a prey patch in the presence of distant volatiles were also more likely to find an odor source (ie, prey patch) from a distance of 20 cm. These two foraging-related behaviors are heritable. A continuous distribution of both behaviors indicated that several to many loci may be responsible for these behavioral traits. Our line-crossing experiments suggested that maternal influence could be excluded. Substantial phenotypic variation in two other foraging-related traits, consumption and oviposition, were also detected among inbred lines. Consumption and oviposition were positively correlated; however, the relationship (slope) varied among inbred lines, suggesting that predatory mites vary in food conversion efficiency. A relationship was detected between patch residence and consumption. Patch location, as one important foraging trait, appeared to be negatively related to consumption, suggesting a trade-off between searching for patches and reproduction.

Feeding ecology and emergence production of annual cicadas (Homoptera: Cicadidae) in tallgrass prairie.

The emergence phenology and feeding ecology of annual cicadas in tallgrass prairie are poorly documented. However, these large insects are abundant, and their annual emergence represents a potentially important flux of energy and nutrients from belowground to aboveground. We conducted a study at Konza Prairie Research Natural Area in eastern Kansas to characterize and quantify cicada emergence and associated energy and nutrient fluxes. We established emergence trap transects in three habitat types (upland prairie, lowland prairie, and riparian forest), and collected cicadas every 3 days from May to September. A subset of trapped cicadas was used for species- and sex-specific mass, nutrient, and stable isotope analyses. Five species were trapped during the study, of which three were dominant. Cicadetta calliope and Tibicen aurifera exhibited significantly higher emergence production in upland prairie than in lowland prairie, and were not captured in forested sites at all. T. dorsata emerged from all three habitat types, and though not significant, showed a trend of greater abundance in lowland grasslands. Two less abundant species, T. pruinosa and T. lyricen, emerged exclusively from forested habitats. Nitrogen fluxes associated with total cicada emergence were estimated to be ∼4 kg N ha-1 year-1 in both grassland habitats, and 1.01 kg N ha-1 year-1 in forested sites. Results of stable isotope analyses showed clear patterns of resource partitioning among dominant cicada species emerging from grassland sites. T. aurifera and C. calliope had δ13C and δ15N signatures indicative of feeding on shallowly rooted C4 plants such as the warm-season grasses dominant in tallgrass prairie ecosystems, whereas T. dorsata signatures suggested preferential feeding on more deeply rooted C3 plants.

Sex pheromone for the brownbanded cockroach is an unusual dialkyl-substituted alpha-pyrone.

Female brownbanded cockroaches, Supella longipalpa, emit a sex pheromone that attracts males from a distance. This pheromone was isolated and identified as 5-(2,4-dimethylheptanyl)-3-methyl-2H-pyran-2-one (which we refer to as supellapyrone), and its structure was confirmed by synthesis. A racemic blend of the synthetic compound elicited behavioral and electrophysiological responses comparable to the natural pheromone across a range of doses. This compound is not only a very different type of cockroach pheromone but also makes up an additional class of natural products--namely, 3,5-dialkyl-substituted alpha-pyrones.

Diel periodicity and influence of age and mating on sex pheromone titer in gypsy moth,Lymantria dispar (L.).

The diel periodicity of sex pheromone titer from pheromone glands of femaleLymantria dispar is described. On the day of emergence (day 0), pheromone titer was generally low; means ranged from 1 to 4 ngcis- 7,8-epoxy-2-methyloctadecane during photophase and gradually increased to 8.4 ng over the course of scotophase. For day-1, -2, and -3 females, the diel fluctuations of titer were more pronounced. Lowest titers (5-9 ng) occurred 0-4 hr after lights-on, and peak titers (19-32 ng) were found 0-4 hr before lights-off. Comparison of the average daily titer among the different age groups (data pooled over six time points at 4-hr intervals) indicated that significantly less pheromone was extracted from glands of day-0 (4.5 ng) than day-1 (12.4 ng), day-2 (15.4 ng), or day-3 females (13.5 ng). No significant differences were found among the three older ages. Femalesin copula exhibited a rapid reduction in titer within the first 0.5 hr of mating initiation (7.6 ng vs. 19.5 ng from virgin females of similar age). After the second 0.5 hr, the reduction in titer was not nearly as marked, falling only to 4.5 ng. Twenty-four hours after mating, titer fell below the limits of detection (0.5 ng). All extracts from pheromone glands of virgin or mated females contained < 1.0 ng of the putative pheromone precursor, 2-methyl-cis-7-octadecene.

Identification of sex pheromone of tomato pinworm,Keiferia lycopersicella (Wals.).

A sex pheromone produced by femaleKeiferia lycopersicella (Walsingham) was isolated and identified as (E)-4-tridecenyl acetate, based on chemical analyses, electroantennogram assays, and field trapping in California and Florida. Males were captured equally well in traps baited with (E)-4-tridecenyl acetate alone or a variety of (Z)- and (E)-4-tridecenyl acetate blends, although theZ isomer was not detected in extracts of female glands.

Identification of sex pheromone of browntail moth,Euproctis chrysorrhoea (L.) (Lepidoptera: Lymantriidae).

A unique sex attractant pheromone was isolated and identified from extracts of ovipositor tips from the female browntail moth (Lepidoptera: Lymantriidae). The pheromone compound, (Z,Z,Z,Z)-7,13,16,19-docosatetraen-1-ol isobutyrate, CH3CH2CH=CHCH2CH=CHCH2CH= CH(CH2)4CH=CH(CH2)6O2CCH(CH3)2, was identified by a combination of gas chromatography, mass spectrometry, and microreactions and was confirmed by synthesis. Traps baited with 5-50 µg of the synthetic pheromone, dispensed from rubber septa treated with an antioxidant and a UV stabilizer, gave male moth captures that were comparable to traps baited with three virgin females. Higher (250 µg) and lower (0.04-2.5 µg quantities of the synthetic pheromone on septa captured somewhat fewer males. Captures were the same for similar quantities of the natural and synthetic pheromone. Minor, inactive components in the tip extract were identified as a mixture of 7- and 8-pentacosanone.

Variability in pheromone composition and periodicity of pheromone titer in potato tuberworm moth,Phthorimaea operculella (Lepidoptera: Gelechiidae).

The ratios and quantities of the pheromone components, (E,Z)-4,7-tridecadien-1-yl acetate (diene) and (E,Z,Z)-4,7.10-tridecatrien-1-yl acetate (triene), in the glands of individual female potato tuberworm moths (Phthorimaea operculella) originating from the United States (California) and Japan (Nagoya) were analyzed by gas chromatography. Quantities of glandextracted pheromone components of Nagoya females fluctuated in a periodic fashion during the photoperiod. Maximal titers coincided with the onset of scotophase (and calling), then gradually declined to minimal levels soon after lights-on. The average daily pheromone quantities decreased significantly as females aged. Both populations exhibited considerable variation in the ratio of the two components. The proportions of triene in the blend ranged from 27% to 88% (triene -X = 56 ± 13% SD; CV = 23%) for California females and from 16% to 71% (42 ± 13%; CV = 31%) for Nagoya females. Nagoya females also stored significantly higher amounts of pheromone in their glands (8.6 ± 3.9 ng) than did California females (2.7 ± 1.4). The differences between the populations, while substantial, would probably not be sufficient to impart a barrier to panmixis, given the wide range of component ratios favored by the males.

Regulation of pheromone biosynthesis by a brain hormone in two moth species.

Experiments were performed to characterize the action of a brain hormone on pheromone biosynthesis in female redbanded leafroller and cabbage looper moths. Results showed that the two species differed in their respective control mechanisms. In the cabbage looper, pheromone titer from decapitated females that received either saline or brain extract injections was not significantly different from control females, suggesting that pheromone biosynthesis was not dependent on the presence of the brain hormone. In contrast, with redbanded leafroller females, studies using radiolabeled acetate incorporation as well as incorporation of deuterium-labeled hexadecanoic acid showed that (i) the brain hormone was required for pheromone biosynthesis, (ii) the brain hormone regulated pheromone biosynthesis by activating synthesis of octadecanoyl and hexadecanoyl intermediates, and (iii) the brain hormone did not control other enzymes in the pathway. Regulation of fatty acid synthetase was unlikely since assays of the enzyme from decapitated and normal females showed no differences in the amount or distribution of the 18- and 16-carbon acyl end products. These results in conjunction with those from organ cultures of the pheromone gland suggest that the brain hormone acts by increasing the substrate supply for fatty acid synthesis.

Temporal patterns of sex pheromone titers and release rates inHolomelina lamae (Lepidoptera: Arctiidae).

Six hydrocarbon components (2-methylhexadecane,n-heptadecane, 2-methylheptadecane, 2-methyloctadecane,n-nonadecane, and 2-methylnonadecane) were identified in sex-pheromone gland extracts and in airborne collections ofHolomelina lamae. Low variability in the ratio of components among individuals indicates tight regulation of blend composition. Minor changes were evident in the quantity and ratio of the blend as a function of time of day. Based on gland extracts, the total quantity of the six components increased from day 1 (X = 6299 ng) to day 4 (X = 7498 ng) and subsequently decreased. No significant correlations were found between total gland contents and wet or dry weights of moths. Emission rates ofH. lamae females were determined from pheromone adsorbed onto Porapak Q. Quantities released peaked shortly after the onset of calling and decreased rapidly as calling continued. Peak release rates ranged from 13 to 350 ng/10 min, and from 37 to 835 ng/60 min. Noncalling females did not emit detectable quantities of pheromone. Based on release rates and the rate of pulsation of the abdominal tip, the average amount released per pulse is not constant. The mean ratio of components released (0.78∶7.45∶ 84.80∶2.84∶2.59∶1.53) was not very different from the ratio of components in gland extracts of 2-day-old females (0.70∶4.19∶90.12∶ 1.65∶1.91∶1.42). We propose that the blend is atomized rather than volatilized from the gland, thus retaining nearly the same ratios in the female's effluvium as in her gland.

A melanomatous carcinoma. A case report and commentary.

A unique cutaneous neoplasm situated wholly in the dermis and showing features of both malignant melanoma and basaloid cell carcinoma is described.

Comparing the effectiveness of sexual communication disruption in the oriental fruit moth (Grapholitha molesta) using different combinations and dosages of its pheromone blend.

The relative efficacy of disruptant blends comprised of different combinations of the Oriental fruit moth's pheromone components was determined in field tests. Disruption was evaluated by comparing male moth catch at synthetic and female-baited traps in disruptant and non-treatment areas. Three atmospheric dosages of a 8-dodecenyl acetate (93.5%Z∶6.5%E) blend, representing two successive 10-fold decreases in concentration (2.5 × 10(-2) g/hectare/day to 2.5 × 10(-4) g/hectare/day) were tested alone and in combination with an additional percentage of (Z)-8-dodecen-1-ol. Male moth orientation to traps was eliminated in plots exposed to the two highest binary acetate dosages. However, significantly more males were captured in synthetic-baited traps in the lowest acetate-alone treatment, indicating a diminution of disruption efficiency. In contrast, inclusion of (Z)-8-dodecen-1-ol in the disruptant blend effected essentially complete disruption of orientation at all concentrations tested. Mating success ofG. molesta pairs confined in small cages apparently was not affected by the presence of relatively high concentrations of the binary acetate and the acetate-alcohol blends. This suggests that habituation and/or adaptation of male response, at least for comparatively "close-range" behaviors, did not occur.