The Role of Multimodal Signals in Species Recognition Between Tree-Killing Bark Beetles in a Narrow Sympatric Zone

2016 ◽  
Vol 45 (3) ◽  
pp. 582-591 ◽  
Author(s):  
Deepa S. Pureswaran ◽  
Richard W. Hofstetter ◽  
Brian T. Sullivan ◽  
Kristen A. Potter
Chemoecology ◽  
2021 ◽  
Author(s):  
Roman Bucher ◽  
Laura M. Japke ◽  
Ayse Gül Ünlü ◽  
Florian Menzel

AbstractThe predator-predator naïveté hypothesis suggests that non-native predators benefit from being unknown to native predators, resulting in reduced intraguild interference with native predators. This novelty advantage should depend on the ability of native predators to recognize cues of non-native predators. Here, we compared ant aggression and lady beetle reaction in four native and the invasive lady beetle species Harmonia axyridis. In addition, we tested whether lady beetle cuticular hydrocarbons (CHCs) are involved in species recognition, which might explain naïveté if the invasive species has a specific CHC profile. To this end, we conducted behavioral assays confronting two native ant species with both living lady beetles and lady beetle elytra bearing or lacking CHCs of different lady beetle species. Finally, we characterized CHC profiles of the lady beetles using GC–MS. In general, the aggression of Lasius niger was more frequent than that of Myrmica rubra and L. niger aggression was more frequent towards most native lady beetle species compared to H. axyridis. The removal of CHCs from lady beetle elytra reduced aggression of both ant species. If CHCs of respective lady beetle species were added on cue-free elytra, natural strength of L. niger aggression could be restored. CHC analyses revealed a distinct cue composition for each lady beetle species. Our experiments demonstrate that the presence of chemical cues on the surface of lady beetles contribute to the strength of ant aggression against lady beetles. Reduced aggression of L. niger towards H. axyridis and reduced avoidance behavior in H. axyridis compared to the equally voracious C. septempunctata might improve the invasive lady beetle’s access to ant-tended aphids.


1977 ◽  
Vol 109 (5) ◽  
pp. 675-686 ◽  
Author(s):  
J. A. McLean ◽  
J. H. Borden

AbstractEthanol and sulcatol (6-methyl-5-hepten-2-ol), primary attractant and population aggregation pheromone, respectively, for Gnathotrichus sulcatus, were deployed alone or in combination on stumps and felled trees in the University of British Columbia Research Forest, Maple Ridge, B.C. On 18 April 1974, four Douglas-fir trees were felled at each of three locations, and four western hemlock trees were felled at each of three other locations. Felled trees and their respective stumps were baited on 26 April. Attacks by G. sulcatus and bark beetles were recorded at weekly intervals until 25 October. G. sulcatus attacks increased rapidly, reaching a maximum in June and July, followed by a steady decrease to October. Attacks by Dendroctonus pseudotsugae, Pseudohylesinus nebulosus, and P. tsugae showed characteristic seasonal trends, but were not correlated to any of the treatments. Over half the G. sulcatus attacks were on stumps, in which attack densities reached 683.5/m2. The greatest numbers of attacks were on stumps and logs baited with sulcatol or sulcatol plus ethanol. There was a significant interaction between sulcatol and ethanol on Douglas-fir but not on western hemlock. Significantly more G. sulcatus attacked ethanol-baited western hemlock stumps and logs than unbaited controls. However, there was no difference between the level of attack on ethanol-baited Douglas-fir and the controls. The role of ethanol is hypothesized to be more of a boring stimulant than a major attractant. Stumps baited with sulcatol and then treated with ethanolic solutions of systemic insecticide could be used to trap and kill field populations, thus reducing numbers of G. sulcatus being transported to log-booming grounds, dryland sorting areas, and sawmills.


Silva Fennica ◽  
2021 ◽  
Vol 55 (5) ◽  
Author(s):  
Markus Melin ◽  
Tiina Ylioja ◽  
Leena Aarnio ◽  
Katri Hamunen ◽  
Seppo Nevalainen ◽  
...  

Bark beetles are amongst the most aggressive pest agents of coniferous forests. Due to this, many boreal countries have designated laws aiming to lower the risk of bark beetle epidemics. Finland’s forest legislation has pre-emptive measures targeted against bark beetles, and for Scots pine ( L.), the law concerns pine shoot beetles ( spp.). This study used data collected around 25 piles of Scots pine roundwood that were harvested in the winter but left in the forest until the following November. Thus, the pine shoot beetles were able to use the piles for breeding. We assessed the number of emerged insects from the piles and the cascading damage they caused in the surrounding forests. All roundwood piles, regardless of their volume, were used by the beetles for breeding. Highest densities of beetle exit holes were found from the parts of the log with thick and intact bark. If the bark of the log was damaged by the harvester head, the number of beetles decreased significantly. Depending on the volume of the roundwood pile, the cascading damage (fallen shoots) was noticeable up to ca. 40–60 m from the roundwood pile. Storing of piles smaller than 50 m did not cause excess damage. The number of fallen shoots per tree was generally below the known thresholds for when growth losses can occur. However, the study was conducted in mature forests, and it can be assumed that the recorded damage levels would severely affect the growth of young pines, raising the question of where to store the roundwood. As with other bark beetles, the role of beetles as damage agents may change in the future, but based on this as well as past studies, the species can be viewed as a notable damage agents only around long-term wood storage sites in the current northern conditions.Pinus sylvestrisTomicus3Tomicus


Author(s):  
Bridget M. Waller ◽  
Eithne Kavanagh ◽  
Jerome Micheletta ◽  
Peter R. Clark ◽  
Jamie Whitehouse

AbstractA wealth of experimental and observational evidence suggests that faces have become increasingly important in the communication system of primates over evolutionary time and that both the static and moveable aspects of faces convey considerable information. Therefore, whenever there is a visual component to any multicomponent signal the face is potentially relevant. However, the role of the face is not always considered in primate multicomponent communication research. We review the literature and make a case for greater focus on the face going forward. We propose that the face can be overlooked for two main reasons: first, due to methodological difficulty. Examination of multicomponent signals in primates is difficult, so scientists tend to examine a limited number of signals in combination. Detailed examination of the subtle and dynamic components of facial signals is particularly hard to achieve in studies of primates. Second, due to a common assumption that the face contains “emotional” content. A priori categorisation of facial behavior as “emotional” ignores the potentially communicative and predictive information present in the face that might contribute to signals. In short, we argue that the face is central to multicomponent signals (and also many multimodal signals) and suggest future directions for investigating this phenomenon.


2021 ◽  
Author(s):  
Dinesh Kandasamy ◽  
Rashaduz Zaman ◽  
Yoko Nakamura ◽  
Tao Zhao ◽  
Henrik Hartmann ◽  
...  

Outbreaks of bark beetles have decimated millions of hectares of conifer forest worldwide in recent years. The ability of these tiny 3-6 mm long insects to kill mature trees over a short period has been ascribed to two factors: (1) mass attacks on the host tree to overcome tree defenses and (2) the presence of fungal symbionts that support successful beetle development in the tree. While the role of pheromones in coordinating mass attacks has been well studied, the role of chemical communication in maintaining the fungal symbiosis is poorly understood. We previously demonstrated that Eurasian spruce bark beetles (Ips typographus) can recognize beneficial fungal symbionts of the genera Grosmannia, Endoconidiophora and Ophiostoma by their de novo synthesized volatile compounds. We hypothesized that the fungal symbionts of the bark beetles might metabolize spruce resin monoterpenes of the beetle host tree, Norway spruce (Picea abies), and that the volatile products could be used as cues by beetles for locating breeding sites with beneficial symbionts. Grosmannia penicillata and other fungal symbionts altered the profile of spruce bark volatiles by converting the major monoterpenes to oxygenated derivatives. Bornyl acetate was metabolized to camphor, and α- and β-pinene to trans-4-thujanol and other oxygenated products. Extensive electrophysiological measurements showed that bark beetles possess olfactory sensory neurons that are selective for these oxygenated symbiont metabolites. Compounds such as camphor and trans-4-thujanol attracted beetles at specific doses in olfactory experiments and stimulated the response of female beetles to a mixture of pheromones. Finally, the fungal symbiont was found to stimulate bark beetle tunneling on diets. Collectively, our results show that oxygenated metabolites of conifer monoterpenes produced by fungal symbionts are used by bark beetles as cues to find these essential microbial symbionts. The oxygenated metabolites may aid beetles in assessing the presence of the fungus, the defense status of the host tree and the density of conspecifics at potential feeding and breeding sites.


2020 ◽  
Vol 287 (1940) ◽  
pp. 20202141
Author(s):  
Amod M. Zambre ◽  
Akshay Khandekar ◽  
Rajesh Sanap ◽  
Clairissa O'Brien ◽  
Emilie C. Snell-Rood ◽  
...  

Interspecific competition can occur when species are unable to distinguish between conspecific and heterospecific mates or competitors when they occur in sympatry. Selection in response to interspecific competition can lead to shifts in signalling traits—a process called agonistic character displacement. In two fan-throated lizard species— Sitana laticeps and Sarada darwini —females are morphologically indistinguishable and male agonistic signalling behaviour is similar. Consequently, in areas where these species overlap, males engage in interspecific aggressive interactions. To test whether interspecific male aggression between Si. laticeps and Sa. darwini results in agonistic character displacement, we quantified species recognition and signalling behaviour using staged encounter assays with both conspecifics and heterospecifics across sympatric and allopatric populations of both species. We found an asymmetric pattern, wherein males of Si. laticeps but not Sa. darwini showed differences in competitor recognition and agonistic signalling traits (morphology and behaviour) in sympatry compared with allopatry. This asymmetric shift in traits is probably due to differences in competitive abilities between species and can minimize competitive interactions in zones of sympatry. Overall, our results support agonistic character displacement, and highlight the role of asymmetric interspecific competition in driving shifts in social signals.


2003 ◽  
Vol 38 (4) ◽  
pp. 602-611 ◽  
Author(s):  
Daniel R. Miller ◽  
John H. Borden

We conducted seven experiments in stands of mature lodgepole pine in southern British Columbia to elucidate the role of host volatiles in the semiochemical ecology of the pine engraver, Ips pini (Say) (Coleoptera: Scolytidae), with particular reference to the behavioral responses of predators and competing species of bark beetles. Our results demonstrated that the attraction of Ips pini and the bark beetle predators Lasconotus complex LeConte (Colydiidae), Thanasimus undatulus (Say) (Cleridae) and a Corticeus sp. (Tenebrionidae) were increased by 3-carene. In contrast, attraction of the bark beetle Pityogenes knechteli Swaine (Scolytidae) to ipsdienol was interrupted by 3-carene and α-pinene. Attraction of L. complex to ipsdienol was increased by γ-terpinene, a compound attractive to the mountain pine beetle, Dendroctonus ponderosae Hopkins (Scolytidae). Terpinolene interrupted the attraction of I. pini to ipsdienol.


2013 ◽  
Vol 59 (4) ◽  
pp. 569-578 ◽  
Author(s):  
Ally R. Harari ◽  
Hadass Steinitz

Abstract The role of female sex pheromones in natural selection, particularly as a means for species recognition to avoid the generation of hybrid offspring with low fitness, has been widely explored and is generally accepted by scholars. However, the significance of sex pheromones in shaping mate choice (sexual selection) and in competition over breeding resources (social selection) has been largely ignored. The effect of sexual selection on sex pheromones as a sexually dimorphic signaling trait has been discounted because the amount of pheromone released by females is typically minute, while the role of sex pheromones in competition over breeding resources (other than mates) has not yet been considered. As a result of natural selection, variation in sex pheromones among females is expected to be low, and males are not expected to choose their mates among phero-mone-releasing conspecific females. Sexual selection, on the other hand, should drive the increase in pheromone variance among females, and males are expected to choose females based on this variation. Moreover, social selection resulting from more general social interactions, for example competition among females for breeding sites and food, should also promote variance among female sex pheromones. Here, we review the current evidence for each of the three selection processes acting on sex pheromones of female moths as an advertising trait. We suggest that the three selection types are not mutually exclusive but rather act together to promote different fitness components in diverse ecological situations.


2012 ◽  
Vol 9 (73) ◽  
pp. 1745-1756 ◽  
Author(s):  
Zsolt Bálint ◽  
Krisztián Kertész ◽  
Gábor Piszter ◽  
Zofia Vértesy ◽  
László P. Biró

The photonic nanoarchitectures responsible for the blue colour of the males of nine polyommatine butterfly species living in the same site were investigated structurally by electron microscopy and spectrally by reflectance spectroscopy. Optical characterization was carried out on 110 exemplars. The structural data extracted by dedicated software and the spectral data extracted by standard software were inputted into an artificial neural network software to test the specificity of the structural and optical characteristics. It was found that both the structural and the spectral data allow species identification with an accuracy better than 90 per cent. The reflectance data were further analysed using a colour representation diagram built in a manner analogous to that of the human Commission Internationale de l'Eclairage diagram, but the additional blue visual pigment of lycaenid butterflies was taken into account. It was found that this butterfly-specific colour representation diagram yielded a much clearer distinction of the position of the investigated species compared with previous calculations using the human colour space. The specific colours of the investigated species were correlated with the 285 flight-period data points extracted from museum collections. The species with somewhat similar colours fly in distinct periods of the year such that the blue colours are well tuned for safe mate/competitor recognition. This allows for the creation of an effective pre-zygotic isolation mechanism for closely related synchronic and syntopic species.


2012 ◽  
Vol 279 (1736) ◽  
pp. 2204-2211 ◽  
Author(s):  
Sharlene E. Santana ◽  
Jessica Lynch Alfaro ◽  
Michael E. Alfaro

The rich diversity of primate faces has interested naturalists for over a century. Researchers have long proposed that social behaviours have shaped the evolution of primate facial diversity. However, the primate face constitutes a unique structure where the diverse and potentially competing functions of communication, ecology and physiology intersect, and the major determinants of facial diversity remain poorly understood. Here, we provide the first evidence for an adaptive role of facial colour patterns and pigmentation within Neotropical primates. Consistent with the hypothesis that facial patterns function in communication and species recognition, we find that species living in smaller groups and in sympatry with a higher number of congener species have evolved more complex patterns of facial colour. The evolution of facial pigmentation and hair length is linked to ecological factors, and ecogeographical rules related to UV radiation and thermoregulation are met by some facial regions. Our results demonstrate the interaction of behavioural and ecological factors in shaping one of the most outstanding facial diversities of any mammalian lineage.


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