R. K. Vander Meer

Absolute configuration of the solenopsins, venom alkaloids of the fire ants

Abstract An effective and practical procedure has been developed that allows the assignment of the absolute configuration of solenopsins from diverse origins us

ANT QUEENS DEPOSIT PHEROMONES AND ANTIMICROBIAL AGENTS ON EGGS

Nordrhein-Westfalen) served as additional references. Flow-cytofluorometric determination (Partec CA II cytometer, Mfinster, Germany) of relative DNA contents of cell nuclei was selected as additional diagnostic assay. The relative genome sizes of salmonids found in tissues of yolk-sac larvae stained with the DNAspecific fluorochrome 4,6-diamidino-2phenylindole differ sufficiently for species differentiation [3, 4, 9, 12]. Again, trout larvae from the breeding stock indicated above served as internal references during flow cytometry. Both diagnostic approaches, whether based on single-locus markers or total genome size, demonstrated that pure-bred offspring of naturally reproducing Atlantic salmon hatched in affluents of the Rhine river in 1994. Our previous finding of F1 hybrids between S. salar and S. trutta in stock bound for restocking the Rhine with Atlantic salmon [6] serves as a warning to continue population-genetic monitoring of the recolonizing salmon population, in order to ensure that reintroduction projects performed to support reappearing stocks are not detrimental to the requirements of species conservation.

Hydrocarbon components of the trail pheromone of the red imported fire ant, Solenopsis Invicta

Abstract Terpenoid trail pheromone components were isolated from whole worker extracts of the red imported fire ant, and identified as Z,E and E,E -α-farnesene, and the previously unreported homofarnesenes Z,Z and Z,E -3,4,7,11-tetramethy1-1,3,6,10-dodecatetraene.

Magnetic orientation in the fire ant,Solenopsis invicta

1. Kudo, R.R.: Protozoology. Springfield, Ill.: Thomas 1954 2. Harland, W.B., Armstrong, R.L., Cox, A.V., Craig, L.E., Smith, A.G., Smith D.G.: A Geological Time Scale 1989. Cambridge: Cambridge Univ. Press 1989 3. Maxwell, R.D.: Introduction to Protozoology. New York: St. Martins Press 1961 4. Smith, G.M.: The Fresh-water Algae of the United States. New York: McGrawHill 1933 5. Tappan, H.: The Paleobiology of Plant Protists. San Francisco: Freeman 1980 6. Poinar, Jr., G.O., Waggoner, B.M., Bauer, U.C.: Science 259, 222 (1993) 7. Thiessen, R., Sprunk, G.C.: U.S. Dept. Interior Tech. Pap. No. 631, p. 1 (1941) 8. Glaessner, M.E: The Dawn of Animal Life: A Biohistorical Study. Cambridge: Cambridge Univ. Press 1984 9. Schuster, EL., in: Handbook of Protoctista (L. Margulis, J.O. Corliss, M. Melkonian, D.J. Chapman, eds.). Boston: Jones and Bartlett 1989 10. Clark, C.G., Gross, G.A.M.: Mol. Biol. Evol. 5, 512 (1988) 11. Christen, R., Ratto, A., Baroin, A., Perasso, R., Grell, K.G., Adoutte, A.: EMBO J. 10, 499 (1991) 12. Allison, C.W., Hilgert, J.W.: J. Paleontol. 60, 973 (1986) 13. Pokorny, V.: Principles of Zoological Micropaleontology. New York: Macmillan 1963 14. Loeblich, A.R., Tappan, H., in: Treatise on Invertebrate Paleontology C(2), Vol. 1. (R.C. Moore, ed.). Lawrence: Geol. Soc. of America and Univ. of Kansas Press 1964 15. Waggoner, B.M.: J. Protozool. 40, 98 (1993) 16. Waggoner, B.M.: PaleoBios (in press)

Biochemical changes in the crop, oesophagus and postpharyngeal gland of colony-founding red imported fire ant queens (Solenopsis invicta)

Abstract Chemical analysis of hydrocarbons, triacylglycerols and free fatty acids present in hexane extracts of the crop, oesophagus and postpharyngeal gland of colony-founding queens of Solenopsis invicta Buren illustrates that the oesophagus enlarges into a thoracic crop concomitant with wing muscle histolysis. The flow of material goes from the crop to the oesophagus, but not to the postpharyngeal gland. In the crop and oesophagus triacylglycerols and the dominant chemical class, whereas the postpharyngeal gland contains primarily hydrocarbons. The pattern of postpharyngeal gland hydrocarbons changes between the time of insemination and 25 days after mating.

Identification of a new member of the PBAN family of neuropeptides from the fire ant, Solenopsis invicta

Neuropeptide hormones produced by neurosecretory cells in the central or peripheral nervous systems regulate various physiological and behavioral events during insect development and reproduction. PBAN/Pyrokinin is a major neuropeptide family, characterized by a 5‐amino‐acid C‐terminal sequence, FXPRLamide. This family of peptides has been implicated in regulating various physiological functions including, pheromone biosynthesis, muscle contraction, diapause induction or termination, melanization, and puparium formation in different insect species. In the present study, we report a new member of the PBAN family from the red imported fire ant, Solenopsis invicta, Soi‐PBAN, composed of 26‐AA (GSGEDLSYGDAYEVDEDDHPLFVPRL). Three additional peptides were deduced from Soi‐PBAN cDNA: 15‐AA (TSQDIASGMWFGPRL), 8‐AA (QPQFTPRL) and 9‐AA (LPWIPSPRL), that correspond to diapause hormone (DH), β‐neuropeptide (NP), and γ‐NP, which are found in many lepidopteran moths. Five peptides, DH, α, β, γ NPs, and PBAN are encoded from PBAN genes of lepidopteran moths, but in the fire ant the α‐NP is missing. Each of the four synthetic peptides from the fire ant Soi‐PBAN cDNA showed significant pheromonotropic activity in a moth model, indicating that these peptides are cross‐reactive. Soi‐β‐NP induced the highest amount of pheromone production of the four peptides evaluated. The Soi‐DH homologue had the lowest pheromonotropic activity, but was still significantly greater than control values. When the deduced amino acid sequences (entire ORF domains) from Soi‐PBAN cDNA were compared with other known sequences, the fire ant was most similar to the honey bee, but phylogenetically distant from moth and beetle species. Soi‐PBAN (26‐AA) unlike the other three peptides shows a low degree of sequence identity with honeybee PBAN (33‐AA). Based on the amino acid sequences encoded from insect PBAN genes identified to date, neuropeptide diversity is correlated with the taxonomic or phylogenetic classification of Insecta. From the present study we report the first neuropeptide identified and characterized from the central nervous system of Formicidae.

Pattern recognition studies of complex chromatographic data sets: Design and analysis of pattern recognition experiments

Abstract Chromatographic fingerprinting of complex biological and environmental samples is a active research area with a large and growing literature. Multivariate statistical and pattern recognition techniques can be effective methods for the analysis of such complex data. However, the classification of complex samples on the basis of their chromatographic profiles is complicated by two factors: (1) confounding of the desired group information by experimental variables or other systematic variations, and (2) random or chance classification effects with linear discriminants. Several interesting projects involving these effects and methods for dealing with the effects are discussed. Complex chromatographic data sets often contain information dependent on experimental variables as well as information which differentiates classes. The existence of these types of complicating relationships is an innate part of fingerprint-type data. ADAPT, an interactive computer software system, has the clustering, mapping, and statistical tools necessary to identify and study these effects in realistically large data sets. In one study, pattern recognition analysis of 144 pyrochromatograms from cultured skin fibroblasts was used to differentiate cystic fibrosis carriers from presumed normal donors. Several experimental variables (door gender, chromatographic column, etc.) were observed to contribute to the overall classification process. Notwithstanding these effects, discriminants were developed from the chromatographic peaks that assigned a given pyrochromatogram to its respective class (cystic fibrosis carrier versus normal) largely on the basis of the desired pathological difference. In another study gas chromatographic profiles of cuticular hydrocarbon extracts obtained from 170 red fire at samples were analyzed using pattern recognition methods. Clustering according to the biological variables of social caste and colony was observed. Previously, Monte-Carlo simulation studies have been carried out to assess the probability of chance classification for nonparametric linear discriminants. The level of expected chance classification as a function of the number of observations, the dimensionality, class membership distribution, and covariance structure of the data were examined. These simulation studies established limits on the approaches that can be taken with real data sets so that chance classifications are improbable.

SEMIOCHEMICALS RELEASED BY ELECTRICALLY STIMULATED RED IMPORTED FIRE ANTS, Solenopsis invicta

The red imported fire ant Solenopsis invicta Buren, has evolved sophisticated chemical communication systems that regulate the activities of the colony. Among these are recruitment pheromones that effectively attract and stimulate workers to follow a trail to food or alternative nesting sites. Alarm pheromones alert, activate, and attract workers to intruders or other disturbances. The attraction and accumulation of fire ant workers in electrical equipment may be explained by their release of pheromones that draw additional worker ants into the electrical contacts. We used chemical analysis and behavioral bioassays to investigate if semiochemicals were released by electrically shocked fire ants. Workers were subjected to a 120 V, alternating-current power source. In all cases, electrically stimulated workers released venom alkaloids as revealed by gas chromatography. We also demonstrated the release of alarm pheromones and recruitment pheromones that elicited attraction and orientation. Arrestant behavior was observed with the workers not electrically stimulated but near those that were, indicating release of unkown behavior-modifying substances from the electrically stimulated ants. It appears that fire ants respond to electrical stimulus by generally releasing exocrine gland products. The behaviors associated with these products support the hypothesis that the accumulation of fire ants in electrical equipment is the result of a foraging worker finding and closing electrical contacts, then releasing exocrine gland products that attract other workers to the site, who in turn are electrically stimulated.

Bioactivity of Cedarwood Oil and Cedrol Against Arthropod Pests

ABSTRACT Heartwood samples from Juniperus virginiana L. were extracted with liquid carbon dioxide, and the bioactivity of carbon dioxide-derived cedarwood oil (CWO) toward several species of ants and cedrol toward ticks was determined. Repellency was tested for ants, and toxicity was tested for ticks. Ants in an outdoor bioassay were significantly repelled by the presence of CWO on a pole leading to a sugar—water solution. Similarly, CWO was a significant repellent barrier to red imported fire ants and prevented them from finding a typical food source. Black-legged tick nymphs exhibited dosage-dependent mortality when exposed to cedrol and at the highest dosage (i.e., 6.3 mg/ml) tested, the cedrol killed 100% of the ticks. These repellency and toxicity results together demonstrate a clear potential for the use of CWO as a pest control agent.

Alteration of cuticular hydrocarbon composition affects heterospecific nestmate recognition in the carpenter ant Camponotus fellah

Nestmate recognition is a ubiquitous phenomenon in social insects as a means to prevent entry of undesired individuals aiming at exploiting the rich nest resources. The recognition cues in ants were shown in a few cases to be cuticular hydrocarbons, although there are a quite number of correlated associations. In the present study we modified the cuticular profiles of workers Camponotus fellah hydrocarbons with cuticular washes from a closely related, yet undescribed species, Camponotus sp. Although these sympatric species are morphologically indistinguishable, cuticular washes of C. sp. contain 9,13-dimethylpentacosane and 11,15-dimethylheptacosane that are either absent or occur as traces in C. fellah. In addition, C. sp. contains significantly greater amounts of 3-methylpentacosane than C. fellah workers. The cuticle modification was done solventless in a manner that minimized disruption to the cuticular structure of the ant being modified. Judging from the 3 focal compounds, such treatment added between 20 and 30% of the original amounts present in C. sp. to the treated C. fellah workers. This addition changed consistently the cuticular hydrocarbon profile of the treated ant. Dyadic assays between C. fellah and their nestmates treated with C. sp. cuticular rinses revealed a significantly higher level of aggression compared to non-treated nestmates. There was no aggression between nestmates of C. sp. These results demonstrate that in heterospecific interactions between the two Camponotus species there is a correlation between cuticular hydrocarbons and a nestmate recognition response, albeit not as high as the response of C. fellah to of C. sp. workers. This is consistent with the hypothesis that cuticular hydrocarbons may play a role in nestmate recognition.