Observations on the Association between Some Buprestid and Cerambycid Beetles and Black Frankincense Resin Inducement

Samburu resin harvesters in northern Kenya maintain that frankincense resin flow from Boswellia neglecta and Commiphora confusa is induced by insect larval activity. Observations on the insects’ larval behaviour support these claims. During the frankincense harvest, buprestid beetle larvae, identified as a Sphenoptera species, are found under B. neglecta resin, eating the monoterpene-rich inner bark, which apparently stimulates the trees to produce copious amounts of fresh resin. The same behaviour was observed with cerambycid beetle larvae, identified as Neoplocaederus benningseni Kolbe, on C. confusa trees. Remarkably, these insects have developed the capacity to digest the resin-saturated inner bark and overcome the toxic, repellent characteristics of oleo-monoterpenes. The frankincense resin also appears to act as a protective covering during the insects’ larval and pupal stages. Excessive tree damage was not noted from these insect invasions. Even though the tree species are from different genera, the resin produced by both is black, with a very similar aromatic chemical profile. The question thus arises as to whether the larval feeding behaviour of these beetle species has an influence, not only on the physical appearance but also on the chemical composition of the resins.

2-Nonanone is a Critical Pheromone Component for Cerambycid Beetle Species Native to North and South America

An increasing body of evidence indicates that cerambycid beetles native to different continents may share pheromone components, suggesting that these compounds arose as pheromone components early in the evolution of the family. Here, we describe the identification and field testing of the pheromone blends of two species in the subfamily Cerambycinae that share 2-nonanone as an important component of their male-produced aggregation-sex pheromones, the South American Stizocera consobrina Gounelle (tribe Elaphidiini) and the North American Heterachthes quadrimaculatus Haldeman (tribe Neoibidionini). Along with 2-nonanone, males of S. consobrina also produce 1-(1H-pyrrol-2-yl)-1,2-propanedione, whereas males of H. quadrimaculatus produce 10-methyldodecanol. Field bioassays conducted in Brazil (targeting S. consobrina) and Illinois (targeting H. quadrimaculatus) demonstrated that adults of both species were attracted only by the blends of both their pheromone components, and not to the individual components. The use of the pyrrole as a critical component for the former species is further evidence that this compound is a common pheromone structure among cerambycines in different biogeographical regions of the world.

Diversity of Cerambycidae (Insecta: Coleoptera) in the Cerrado of Central Brazil using a new type of bait

The Cerambycidae family (Insecta: Coleoptera) has approximately 38 thousand species. In Brazil, more than 4,300 species and 1,050 genera are registered, and despite the ecological and agricultural importance of this family, no study has yet been done in the Cerrado of the Distrito Federal (Brazil). The objective of this study was to evaluate the richness and abundance of Cerambycidae in the Cerrado area using two types of fruits (banana and pineapple), fermented with sugarcane juice, as bait and to verify whether the richness is influenced by climate variables. The work was carried out in an area of the cerrado sensu stricto at Água Limpa Farm in the Distrito Federal. Beetles were collected weekly using 40 bait traps with two types of fruits that remained in the field for 12 uninterrupted months (November 2013 to October 2014). The traps were installed 1.50 m above the ground level, distributed in four 80 m transects, and spaced 20 m apart. A total of 1,599 individuals, belonging to 13 genera and different 19 species, were collected. The main species were as follows: Oxymerus basalis (Dalman, 1823) representing 78.3%, Retrachydes thoracicus thoracicus (Olivier, 1790) representing 9.9%, and Chydarteres bicolor (Fabricius, 1787) representing 4.5% of the total specimens collected. There was a significant difference in richness and abundance of Cerambycidae among the baits evaluated, with the pineapple bait presenting the highest values. The greatest number of individuals and species occurred soon after the first rains, especially in November. Temporal variation was confirmed through Rayleigh’s uniformity test, following the seasonality of the Cerrado, with the greatest number of individuals and species found in the rainy season. Temperature and humidity influenced the richness of cerambycid beetles. This is the first work carried out with pineapple fermented with sugarcane juice as bait to capture Cerambycidae, and this type of bait proved to be efficient for the collection of insects, comparable in efficiency to the synthetic baits that are normally used. All species collected were new distribution records for the Distrito Federal (Brazil).

Discovery of a phoretic association between Bursaphelenchus doui (Nematoda: Aphelenchoididae) and Monochamus saltuarius and Acalolepta sejuncta (Coleoptera: Cerambycidae)

Summary To investigate the phoretic association between nematodes in the genus Bursaphelenchus and cerambycid beetles in north-eastern Japan, Pinus densiflora logs were placed in two pine forests in the towns of Yamada and Hiranai as beetle oviposition sites. At 1-2 years after oviposition, adults of Monochamus saltuarius emerged from the logs placed in Yamada and adults of Acalolepta sejuncta and A. fraudatrix emerged from the logs placed in Hiranai, and Bursaphelenchus nematodes were recovered from two of these species (M. saltuarius and A. sejuncta). Morphometrics and a phylogenetic analysis of the internal transcribed spacer regions 1 and 2 and the 5.8S ribosomal RNA gene indicated that both of these nematode populations were B. doui, which has previously only been known to use M. subfasciatus and A. fraudatrix as vectors. Therefore, this study demonstrated that this nematode utilises at least four species of beetles belonging to two genera as vectors in the field.

Variations on a Theme: Two Structural Motifs Create Species-Specific Pheromone Channels for Multiple Species of South American Cerambycid Beetles

We describe the identification, synthesis, and field-testing of aggregation-sex pheromones, or likely pheromone candidates, of seven species of South American cerambycid beetles in the subfamily Cerambycinae, of the tribes Eburiini and Neoibidionini. Analyses of extracts of volatiles released by adult males revealed that Eburodacrys dubitata White produce 11-methyltridecanal, whereas the males of Eburodacrys assimilis Gounelle, Eburodacrys flexuosa Gounelle, and Eburodacrys lenkoi Napp and Martins produce blends of this compound, along with its analog 10-methyldodecanal. In contrast, males of Compsibidion graphicum (Thomson) and Compsibidion sommeri (Thomson) produce blends of 10-methyldodecanal and its corresponding alcohol 10-methyldodecanol. The results from field bioassays with synthetic compounds showed that each species was specifically attracted to traps containing their reconstructed pheromone blend. However, E. assimilis was not trapped, possibly due to inhibition by non-natural enantiomers in the racemic test compounds. During the trials for the Compsibidion species, adults of another cerambycid species, Tetraopidion mucoriferum (Thomson), were captured in significant numbers in traps baited with 10-methyldodecanol, suggesting that this compound is a pheromone component for this species. This study demonstrates another case of conservation of pheromone structures within South American cerambycid species. It also highlights how blends of closely related structures, differing only in chain length or functional group, make the evolution of species-specific pheromone channels possible.