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15 recordsLinked to original sources
PubMed2026

Cross-domain cooperation drives nutrient acquisition and metabolism in the bark beetle holobiont.

Microbial symbiosis underpins host adaptation, yet mechanisms of metabolic integration in holobionts remain unclear. Using metatranscriptomics, genomics, and metabolic assays, we investigated gut microbiome interactions in the European spruce bark beetle (Ips typographus). We observed metabolic complementarity among symbionts and host, forming cross-domain networks that support nutrient acquisition. Nitrogen recycling revealed strong interdependence: no single partner possessed a complete uric acid degradation pathway, but combined evidence supports a distributed pathway spanning beetle, Bacteria, and fungi. Additionally, bacterial nitrate reduction to ammonia indicates a potential nitrogen influx, making otherwise inaccessible inorganic nitrogen available to the host. Shaped by microbial interactions, symbionts also likely supply specific amino acids, while vitamin metabolism showed cross-domain co-metabolism, with Bacteria as main producers of B vitamins, while host and fungi modulated interconversion. Carbohydrate degradation was highly partitioned; bacteria target xylan and pectin, while fungi contribute to glucan breakdown. Crucially, our data provide indirect evidence that the beetle may contribute to complete cellulose degradation, highlighting an underappreciated host role in lignocellulose processing. In terms of enzymatic functional diversity, the bacteriome emerged as the most important microbiome component-an observation that contrasts with the traditional focus on fungi and underscores the need to consider bacterial contributions in insect symbioses. Despite life-stage variation, core metabolic functions remained stable. Overall, metabolic interdependence, rather than microbial composition alone, structures holobiont function. These results highlight functional redundancy and ecological resilience, emphasizing the importance of microbial cooperation and host-microbe metabolic evolution.

Bark beetle↗
PubMed1976

Selective production of cis- and trans-verbenol from (-)-and (+)-alpha by a bark beetle.

A unique biological system whereby optical isomers are selectively transformed to geometrical isomers is demonstrated in Ips paraconfusus. Exposure of adult male and female beetles to vapor of (-)-alpha-pinene resulted in the production of (+)-cis-verbenol, a pheromone of this species, whereas (+)-alpha-pinene was oxidized to (+)-trans-verbenol. It appears, therefore, that the ability of a bark beetle to produce its aggregation pheromone can be governed by the chirality of a precursor in the host tree.

Animals↗
PubMed1977

Ultrastructure of juvenile hormone-induced degenerating flight muscles in a bark beetle, Ips paraconfusus.

Topical application of 5 microgram of a juvenile hormone analogue (JHA), ZR-615, to female callow adults of Ips paraconfusus induced degeneration of the dorsoventral flight muscles. Within 24 h after JHA-treatment the diameter of the myofibrils was reduced to almost half due to the lysis of the peripheral myofilaments. Mitochondria showed conspicuous degenerative changes like swelling, dissolution of the matrix or presence in the matrix of dense filamentous material or myelin-like figures. Degeneration of the mitochondria seemed to take place inside isolation membranes derived from sarcoplasmic reticulum. A number of granular osmiophilic bodies appeared in the sarcoplasm. Three days after JHA-treatment the muscles were very thin and sheath-like. Most of the mitochondria had already degenerated. The dense sarcoplasm contained numerous crystalline bodies. The granular dense bodies were also more frequent. The myofibrils were comprised of only occasional small bundles of myofilaments. The tubules of the T system enclosed an amorphous material. The nuclei and the tracheal system remained intact but they were crowded due to the decreased volume of the muscle. In some specimens degeneration of the myofibrils and mitochondria was completed by the third day. No sign of degeneration was observed in the flight muscles of acetone treated control insects.

Animals↗
PubMed1970

Sex pheromones: abolition of specificity in hybrid bark beetles.

Specificity of sex pheromones maintains breeding isolation among three closely related species of spruce-infesting Ips. Hybrids produced in the laboratory were intermediate to the parent species in both attractiveness and response. Pheromones and pheromone receptor types in the hybrids are probably mixtures of those of the parent species.

Animals↗
PubMed1975

[Specificity of the response of monogamous and polygamous Scolytidae to the attraction exerted by digestive residues (feces)].

This paper will emphasize studies of sex attractant in the polygamus species of Scolytidae genus (Phloeosinus, Pityogenes, Pityophthorus) and monogamus species genus Cryphalus, Blastophagus. The secondary attractant or "sex pheromone" was localized in the frass material produced by male beetle in polygamus bark beetles and by female in monogamus species; pheromone specificity has been studied in differents species Phloeosinus, Pityogenes, Pityophthorus, etc. This specificity was evaluated by exposing groups of female beetles to comparable quantities of frass from male polygamus bark beetles.

Animals↗
PubMed1968

Response of Ips confusus to synthetic sex pheromones in nature.

The first flight response of bark beetles to synthetic sex pheromones under natural conditions is reported. Two insect species predaceous on this bark beetle also responded. The synthetic compounds delivered in an airstream from a substrate of Carbowax 20M on Chromosorb A appear to elicit the same response as the natural attractant from male-infested bolts of ponderosa pine elicits.

Animals↗
PubMed1976

Role of phermones and kairmones for insect suppression systems and their possible health and environmental impacts.

Insects produce pheromones as a chemical communication system to facilitate reproduction. These highly active chemical attractants have been synthesized for some of the most important insect pests, including the boll weevil, gypsy moth, codling moth, tobacco budworm, European corn borer, and several bark beetles. While none of the synthetic sex attractants have yet been developed for use in insect control, they offer opportunities for the future both as control agents and to greatly improved insect detection. Investigations are underway on insect trapping systems employing the phermones and on air permeation techniques to disrupt insect reproduction. The pheromones are generally highly species-specific and are not likely to pose hazards to nontarget organisms in the environment. Toxicological studies indicate that they are low in toxicity to mammals, birds, and fish, but adequate toxicological data are necessary before they can be registered for use in insect control. Another new class of compounds called kaironomes has been discovered. These chemicals are involved in the detection of hosts or prey by insect parasites and predators. Kairomones may prove useful in manipulating natural or released biological agents for more effective biological control of insect pests. No information is yet available on the toxicology of these chemicals.

Air↗