Effects of Terpenoid Compounds on Growth of Symbiotic Fungi Associated with the Southern Pine Beetle

by | Jun 16, 2022 | 1981-1990 Publications

Abstract

The blue-stain fungus Ceratocystis minor and the two mycangial fungi of the southern pine beetle (Dendroctonus frontalis) were grown in saturated atmospheres of volatile compounds from loblolly pine. The monoterpenes and α- and β- pinene significantly stimulated the linear growth of one of the mycangial fungi, a Sporothrix species. Growth of the other, a basidiomycete, was significantly inhibited by α- and β- pinene and by most of the other compounds tested. Linear growth of C. minor was not significantly affected by α-pinene but was inhibited by β- pinene. A phenylpropanoid, 4-allylanisole, was highly inhibitory to all three fungi. Results suggest that the production of this compound may be an important loblolly pine defense mechanism against attack by the southern pine beetle and fungi associated with it.

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BRIDGES, JR. 1987a. “EFFECTS OF TERPENOID COMPOUNDS ON GROWTH OF SYMBIOTIC FUNGI ASSOCIATED WITH THE SOUTHERN PINE-BEETLE.” Phytopathology77 (1): 83–85. https://doi.org/10.1094/Phyto-77-83.

Mycangial Fungi of Oendroetonns frontalis (Coleoptera: Scolytidae) and their Relationship to Beetle Population Trends

by | Jun 16, 2022 | 1981-1990 Publications

Abstract

Females from eight endemic populations of the southern pine beetle, Dendroctonus frontalis Zimmerman, were examined to determine which of two fungi were present in the mycangium. The fungi Ceratocystis minor (Hedgcock) Hunt var. barrasii Taylor and an unidentified basidiomycete were found together in 10 to 20% of the beetles. Less than 10% of each population had neither fungus in the mycangium, whereas 13 to 47% had C. minor var. barrasii alone. The basidiomycete was the most prevalent fungus in most populations and occurred alone in 38 to 75% of the beetles. Frequency of occurrence of the fungi varied significantly among the eight populations studied. The mean mass of individual females varied significantly (P < 0.01), depending on which fungus was present in the mycangium. Weights varied as follows: females with only the basidiomycete > those with both fungi > those with only C. minor var. barrasii > those with neither fungus. Brood increase ratio and brood survival were significantly related to the frequency of occurrence of the mycangial fungi. The strongest relationship was found between these indices of population trends and the frequency of occurrence of the basidiomycete. Both indices were negatively correlated with the percentage of C. minor var. barrasii in a population.

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BRIDGES, JR. 1983. “MYCANGIAL FUNGI OF DENDROCTONUS-FRONTALIS (COLEOPTERA, SCOLYTIDAE) AND THEIR RELATIONSHIP TO BEETLE POPULATION TRENDS.” Environmental Entomology12 (3): 858–61. https://doi.org/10.1093/ee/12.3.858.

Effects of Juvenile Hormone on Pheromone Synthesis in Dendroctonus frontalis

by | Jun 16, 2022 | 1981-1990 Publications

Abstract

One-day-old male and female Dendroctonus frontalis produced the pheromone trans-verbenol when treated topically with JH-II or methoprene. JH stimulated production of endo-brevicomin in 5-day-old and emergent males. These results suggest that JH mediates pheromone synthesis in D. frontalis, although the stimulus initiating JH production is not known. JH treatment generally decreased the pheromone content of 5-day-old or emergent adults, indicating that pheromone release may also be stimulated.

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BRIDGES, JR. 1982. “EFFECTS OF JUVENILE-HORMONE ON PHEROMONE SYNTHESIS IN DENDROCTONUS-FRONTALIS.” Environmental Entomology11 (2): 417–20. https://doi.org/10.1093/ee/11.2.417.

Nitrogen-Fixing Bacteria Associated with Bark Beetles

by | Jun 16, 2022 | 1981-1990 Publications

Abstract

Nitrogen-fixing Enterobacter agglomerans and Enterobacter spp. were consistently isolated from the bark beetle Dendroctonus terebrans. Large populations of nitrogen-fixing bacteria were found with the beetle, although no in situ acetylene reduction was demonstrated. The constant occurrence of nitrogenfixing bacteria with D. terebrans suggests a symbiotic relationship. Nitrogen-fixing bacteria were also isolated from the bark beetles Dendroctonus frontalis and Ips avulsus.

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BRIDGES, JR. 1981. “NITROGEN-FIXING BACTERIA ASSOCIATED WITH BARK BEETLES.” Microbial Ecology7 (2): 131–37. https://doi.org/10.1007/BF02032495.

Kairomonal Responses of Coleoptera, Monochamus titillator (Cerambycidae), Thanasimus dubius (Cleridae), and Temnochila virescens (Trogositidae), to Behavioral Chemicals of Southern Pine

by | Jun 16, 2022 | 1981-1990 Publications

Abstract

The kairomonal responses of the sawyer beetle, Monochamus titillator (F.), and two predators, Thanasimus dubius (F.) and Temnochila mrescens (F.), to southern pine bark beetle attractant and inhibitor mixtures were monitored in a series of replicated field bioassays. Tests were conducted in the presence and absence of measurable populations of the southern pine beetle, Dendroctonus frontalis Zimmermann. At three different test sites, M. titillator responded to traps baited with pheromone mixtures attractive to southern Ips spp. (I. avulsus [Eichhoff], I. grandicollis [Eichhoffl, I. calligraphus [Germar]), particularly those also containing D. frontalis inhibitor. This sawyer exhibited a reduced numerical response to a combination of D. frontalis attractant and D. frontalis inhibitor, but no significant response to traps baited solely with D. frontalis attractant. This is the first report of a sawyer beetle responding to pheromones of coinhabiting pine bark beetles. The predator T. dubius was captured in greatest numbers in traps baited with D. frontalis attractant, and in significantly lesser numbers in traps containing Ips attractant. In contrast to T. dubius, the predator T. mrescens responded almost exclusively to Ips attractant and showed little response to D. frontalis attractant. These kairomonal responses explain previously observed temporal and spatial arrival patterns of these insect associates to bark-beetle-infested southern pines.

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BILLINGS, RF, and RS CAMERON. 1984. “KAIROMONAL RESPONSES OF COLEOPTERA, MONOCHAMUS-TITILLATOR (CERAMBYCIDAE), THANASIMUS-DUBIUS (CLERIDAE), AND TEMNOCHILA-VIRESCENS (TROGOSITIDAE), TO BEHAVIORAL CHEMICALS OF SOUTHERN PINE BARK BEETLES (COLEOPTERA, SCOLYTIDAE).” Environmental Entomology13 (6): 1542–48. https://doi.org/10.1093/ee/13.6.1542.