The aggregation pheromones of bark beetles: Progress and problems

1976 ◽  
Vol 63 (12) ◽  
pp. 550-555 ◽  
Author(s):  
J. P. Vité ◽  
W. Francke
Keyword(s):  
Bark Beetles ◽  
Aggregation Pheromones

scholarly journals Tree resin flow dynamics during an experimentally induced attack by Ips avulsus, I. calligraphus, and I. grandicollis

2019 ◽  
Vol 49 (1) ◽  
pp. 53-63 ◽  
Author(s):  
Sander O. Denham ◽  
David R. Coyle ◽  
A. Christopher Oishi ◽  
Bronson P. Bullock ◽  
Kari Heliövaara ◽  
...  
Keyword(s):  
South Carolina ◽  
Bark Beetle ◽  
Bark Beetles ◽  
Aggregation Pheromones ◽  
Tree Defenses ◽  
Pinus Taeda L ◽  
Stochastic Events ◽  
Resin Defenses ◽  
North And South

The success of tree colonization by bark beetles depends on their ability to overcome host tree defenses, including resin exudation and toxic chemicals, which deter bark beetle colonization. Resin defenses during insect outbreaks are challenging to study in situ, as outbreaks are stochastic events that progress quickly and thus preclude the establishment of baseline observations of non-infested controls. We use synthetic aggregation pheromones to demonstrate that confined Ips bark beetle herbivory can be successfully initiated to provide opportunities for studying interactions between bark beetles and their hosts, including the dynamics of constitutive and induced resin exudation. In Pinus taeda L. plantations between 12 and 19 years old in North and South Carolina, U.S., trees were affixed with pheromone lures, monitored for evidence of bark beetle attacks, and resin samples were collected throughout the growing season. Baiting increased beetle herbivory to an extent sufficient to produce an induced resin response. Attacked trees exuded about three times more resin at some time than control trees. This supports previous work that demonstrated that information on constitutive resin dynamics alone provides an incomplete view of a host tree’s resistance to bark beetle attack.

scholarly journals Colonization of weakened trees by mass-attacking bark beetles: no penalty for pioneers, scattered initial distributions and final regular patterns

2018 ◽  
Vol 5 (1) ◽  
pp. 170454 ◽  
Author(s):  
Etienne Toffin ◽  
Edith Gabriel ◽  
Marceau Louis ◽  
Jean-Louis Deneubourg ◽  
Jean-Claude Grégoire
Keyword(s):  
Bark Beetles ◽  
Aggregation Pheromones ◽  
Group Foraging ◽  
Suitable Host ◽  
New Host ◽  
Living Well ◽  
Spruce Bark ◽  
Spatio Temporal ◽  
Initial Distributions ◽  
Male Beetle

Bark beetles use aggregation pheromones to promote group foraging, thus increasing the chances of an individual to find a host and, when relevant, to overwhelm the defences of healthy trees. When a male beetle finds a suitable host, it releases pheromones that attract potential mates as well as other ‘spying’ males, which result in aggregations on the new host. To date, most studies have been concerned with the use of aggregation pheromones by bark beetles to overcome the defences of living, well-protected trees. How insects behave when facing undefended or poorly defended hosts remains largely unknown. The spatio-temporal pattern of resource colonization by the European eight-toothed spruce bark beetle, Ips typographus , was quantified when weakly defended hosts (fallen trees) were attacked. In many of the replicates, colonization began with the insects rapidly scattering over the available surface and then randomly filling the gaps until a regular distribution was established, which resulted in a constant decrease in nearest-neighbour distances to a minimum below which attacks were not initiated. The scattered distribution of the first attacks suggested that the trees were only weakly defended. A minimal theoretical distance of 2.5 cm to the earlier settlers (corresponding to a density of 3.13 attacks dm −2 ) was calculated, but the attack density always remained lower, between 0.4 and 1.2 holes dm −2 , according to our observations.

Saproxylic community, guild and species responses to varying pheromone components of a pine bark beetle

2013 ◽  
Vol 103 (5) ◽  
pp. 497-510 ◽  
Author(s):  
Iñaki Etxebeste ◽  
José L. Lencina ◽  
Juan Pajares
Keyword(s):  
Bark Beetle ◽  
Bark Beetles ◽  
Sustainable Forest Management ◽  
Gaussian Model ◽  
Aggregation Pheromones ◽  
Delayed Response ◽  
Beetle Species ◽  
Saproxylic Beetle ◽  
By Catch ◽  
Associated Species

AbstractSome bark beetle species (Coleoptera: Scolytinae) produce aggregation pheromones that allow coordinated attack on their conifer hosts. As a new saproxylic habitat is founded, an assemblage of associated beetles kairomonally respond to bark beetle infochemicals. Ips sexdentatus is one of the major damaging insects of Pinus spp. in Southern Europe. Its response to varying ipsenol (Ie) percentages in relation to ipsdienol (Id) was studied in northwestern Spain, along with the entire saproxylic beetle assemblage captured at multiple-funnel traps. Response profile modeling was undertaken for I.sexdentatus sexes and sex-ratios, associated species and for selected trophic groups using a reference Gaussian model. In addition, the effects on the saproxylic assemblages were analyzed. I. sexdentatus response curve peaked at 22.7% Ie content, while remaining taxa that could be modeled, peaked above ca. 40% Ie. Predator guilds showed a linear relationship with Ie proportion, while competitors showed a delayed response peak. Consequently, species assemblages differed markedly between varying pheromone component mixtures. Given that the evaluated pheromonal proportions mimicked that of logs being colonized by I. sexdentatus, results suggested that the registered differential responses at different levels might provide I.sexdentatus with a temporal window that maximizes conspecific attraction while reducing interference with competitor and predatory guilds. Described responses might help improve the monitoring of the population status of target bark beetles and their associates, but also point toward the by-catch of many natural enemies, as well as rare saproxylic beetle species, interfering with the aims of sustainable forest management.

scholarly journals Host-Tree Monoterpenes and Biosynthesis of Aggregation Pheromones in the Bark BeetleIps paraconfusus

2012 ◽  
Vol 2012 ◽  
pp. 1-10 ◽  
Author(s):  
John A. Byers ◽  
Göran Birgersson
Keyword(s):  
Aggregation Pheromone ◽  
Pinus Ponderosa ◽  
Bark Beetles ◽  
De Novo ◽  
Host Tree ◽  
Ips Paraconfusus ◽  
Pheromone Biosynthesis ◽  
Host Plant Selection ◽  
Aggregation Pheromones ◽  
Host Trees

A paradigm developed in the 1970s thatIpsbark beetles biosynthesize their aggregation pheromone components ipsenol and ipsdienol by hydroxylating myrcene, a host tree monoterpene. Similarly, hostα-pinene was hydroxylated to a third pheromone componentcis-verbenol. In 1990, however, we reported that amounts of ipsenol and ipsdienol produced by maleIps paraconfusus(Coleoptera: Scolytinae) feeding in five host pine species were nearly the same, even though no detectable myrcene precursor was detected in one of these pines (Pinus sabiniana). Subsequent research showed ipsenol and ipsdienol are also biosynthesized from smaller precursors such as acetate and mevalonate, and thisde novopathway is the major one, while host tree myrcene conversion by the beetle is the minor one. We report concentrations of myrcene,α-pinene and other major monoterpenes in five pine hosts (Pinus ponderosa,P. lambertiana,P. jeffreyi,P. sabiniana, andP. contorta) ofI. paraconfusus. A scheme for biosynthesis of ipsdienol and ipsenol from myrcene and possible metabolites such as ipsenone is presented. Mass spectra and quantities of ipsenone are reported and its possible role in biosynthesis of aggregation pheromone. Coevolution of bark beetles and host trees is discussed in relation to pheromone biosynthesis, host plant selection/suitability, and plant resistance.

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