Fig 2 - uploaded by Lars-Ove Wikars
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Larva of the pine-sawyer beetle Monochamus sutor in the same position as when sound is made. A) bark, B) air-filled space, C) wood, D) hibernation tun nel.
Source publication
In a study in Sweden, 1-year old larvae of Monochamus sutor produced regular chirping sounds, easily heard up to 10 m away. Larvae were positioned within their hibernation tunnel in sapwood of recently fire-killed spruce (Picea) and pine (Pinus) trees. Their heads were directed outwards, and the sound was probably produced by the scratching of thei...
Contexts in source publication
Context 1
... found. These were most likely one year old, as colonisation by pine-sawyer beetles take place immediately after fires, at least when fires occur during July and August (Forsslund 1934 and personal observa tions). The larvae were positioned in the sap wood, each inside its hibernation tunnel, with their heads projecting outwards against the bark (Fig. 2). They presumably produced the sound by scratching their mandibles against the bark. As the sub-cortical tissue of a tree is more or less consumed after attack the space beneath the bark is air-filled and can act as a resonance chamber. No feeding was observed in connection with sound production. Hence we can exclude the possibility ...
Context 2
... central and northern Sweden, the pine sawyer beetle has a two year life-cycle. During the first summer of development, larvae live entirely sub-cortically whereas in their second summer larvae make a hibernation tunnel into the sapwood (Fig. 2). However, extensive feeding excursions are still made under bark adjacent to the hiberna tion tunnel. After passing a second winter, larvae pupate early in the following summer. The pupa is formed at the innermost end of the now U -shaped, 5-10 cm deep and 20-25 cm long tunnel. Emergence of adult beetles take place in July to August ...
Context 3
... ibland langre. Flera ljud kunde horas samtidigt och de var klart urskiljbara pa over 10 meters hall i lugnt vader. Genom att exakt lokalisera Jj udkallan med horseln och snabbt riva av barken hittades larver av tall back Monochamus sutor L. (Coleoptera: Ceram bycidae). De satt med huvudet riktat utat i sin overvintringsgang inuti veden (Fig. 2). Ljudet frambringas fOrmodligen genom att larverna skra par kakarna mot barken. Inga direkta gnag kunde observeras i samband med lj udalstringen, varfOr vi anser oss kunna utesluta att ljuden ar en bipro dukt av detta. Da ljudalstringen potentiellt kan locka till sig fiender utifran, som hackspettar och parasitoida insekter, bor ...
Citations
... This was evident with high gallery incidence and the formation of galleries that overlapped each other destroying the thin partition of sapwood that separated individual larvae during development. This suggests aggressive interference competition (conspecific facultative predation) was occurring [49][50][51]. Younger larvae may have become more susceptible to cannibalism by more mature larvae [8,25,27,28], and larvae that had been delayed in their development were potentially eating the frass made by older larvae [2]. However, feeding was concentrated in certain areas of sapwood, while in other areas, sapwood remained largely uneaten. ...
The attack patterns, infestation success and larval development of woodborers within living trees are complex and are largely shaped by host tree characteristics. Following a severe drought in a native eucalypt forest where outbreak densities of a native Australian beetle, the eucalyptus longhorned borer (Phoracantha semipunctata), occurred, a tree dissection study was conducted in Australia. This involved felling 40 trees each of jarrah (Eucalyptus marginata) and marri (Corymbia calophylla) that were cut into 1-m sections and neonate larval galleries, larvae in pupal cells and adult borer emergence were measured and added to give total numbers per tree to determine the within-tree distribution and survival of P. semipunctata. There was a significant impact on larval survival in both species, in contrast, pupal survival remained high. Within-tree distribution of P. semipunctata was directional with borer emergence and incidence of larval galleries both negatively associated with tree section height above the ground and positively associated with section diameter and bark thickness, reaching a maximum towards the base of trees. High incidence and survival in lower thicker tree sections indicate a more conducive environment for larval development, in contrast to poor larval survival in smaller thinner sections at the top of trees. The dependence of larval survival on tree characteristics controlling the within-tree distribution of borer emergence is emphasized, and needs to be considered when estimating the spread of borer populations during outbreaks.
... Cerambycidae larvae are exclusively phytophagous or xylophagous (Linsley, 1959;Hanks, 1999;Jang et al., 2015;Haack, 2017), except in situations of accidental predation when the larvae meet in a gallery (Victorsson and Wikars, 1996). The types of host plants (e.g., broadleaved trees, conifers, and herbs), host plant parts (e.g., twigs, roots, stems, and sapwood), host tissues (e.g., inside bark, under bark, sapwood, and heartwood), host ranges (e.g., monophagy, oligophagy, and polyphagy), and host condition (e.g., living, stressed, weakened, and dead) are important factors associated with cerambycid host plant selection. ...
... The ecological meaning of Scarabaeidae larval stridulations is not well understood 24 although they are mostly interpreted as a territorial defence technique, i.e. stridulating larvae signal their presence to other larvae to avoid competition for resources and to forgo cannibalism 28 . Cannibalism is not uncommon 28,37 and is also known for Melolontha spp larvae. In a laboratory experiment it was observed that Lucanus cervus (LINNAEUS, 1758) larvae stridulated much more frequently directly after they were placed in a terrarium than later on 27 . ...
Root-feeding Scarabaeidae larvae can pose a serious threat to agricultural and forest ecosystems, but many details of larval ecology are still unknown. We developed an acoustic data analysis method based on active sound production by larvae (i.e. stridulations) for gaining new insights into larval ecology. In a laboratory study, third instar larvae of the Common Cockchafer (Melolontha melolontha) (n = 38) and the Forest Cockchafer (M. hippocastani) (n = 15) kept in soil-filled containers were acoustically monitored for 5 min each, resulting in the first known stridulation recordings for each species. Subsequent continuous monitoring of three M. hippocastani larvae over several hours showed that a single larva could stridulate more than 70 times per hour, and stridulation rates increased drastically with increasing larval abundance. The new fractal dimension-based data analysis method automatically detected audio sections with stridulations and provided a semi-quantitative estimate of stridulation activity. It is the first data analysis method specifically targeting Scarabaeidae larvae stridulations in soils, enabling for the first time non-invasive species-specific pest monitoring.
... Under these conditions, smaller logs could harbour higher population densities, especially if a better wood quality decreases the larval tunnelling rate and cannibalistic encounters between larvae. Larval cannibalism, especially in crowded populations, may be a significant source of mortality in cerambycids (Hanks et al. 1993;Victorsson and Wikars 1996;Anbutsu and Togashi 1997). However, our few observations on cannibalistic behaviour Linear regression between wood diameter (bolts from either trunks or branches) and population density [log 10 (x + 1) transformed] in Cerambyx welensii (Cw) and Prinobius myardi (Pm). ...
Oak open woodlands are widespread in southwestern Iberia and present outstanding ecological, biodiversity and socio-economic values. Evergreen species (holm and cork oaks) are prevalent but deciduous oaks may be also locally important. Three large xylophagous cerambycids are associated to these oaks, Cerambyx welensii (Cw), C. cerdo (Cc) and Prinobius myardi (Pm). Like other saproxylic insects, these cerambycids are essential to the nutrient cycle, wood degradation and tree hollow formation, significantly contributing to biodiversity in oak forests. These cerambycids may also potentially colonise healthy living trees and become harmful or pest species. Factors driving their larval ecology are almost unknown, especially in oak forests harbouring mixed populations living in sympatry. Wood samples (n = 500 bolts) from 348 colonised trees were examined during 2011–2016 across the Extremadura region (41,634 km²). Bolts were measured, scored into five wood quality classes, dissected, and all target cerambycids were collected, measured, reared and taxonomically identified. We then determined species-specific prevalence, niche breadth, niche overlap, age structure and population density depending on wood quality, host preference, tree part, wood size, altitude and sun exposure. Wood quality and host preference were major factors segregating interspecific resource partitioning. Cw was prevalent on cork oak decayed wood, and Pm on holm oak degraded wood. Host tree part was involved in Cerambyx larval niche segregation, with Cw prevalent in the fork/branches and Cc in the trunk/base. Pm was never found inhabiting deciduous oaks. Our results may be useful to improve sustainable forest management practices in Iberian oak open woodlands.
... Cerambycid larvae are phytophagous (Linsley 1959;Hanks 1999;Slipinski and Escalona 2013), although facultative inter-and intraspeci c predation has been observed when larvae encounter other individuals within the host plant as they construct their galleries (Togashi 1990;Victorsson and Wikars 1996;Dodds et al. 2001;Ware and Stephen 2006;Schoeller et al. 2012). Cerambycid larvae feed on a wide diversity of plant species, plant parts, plant tissues, as well as on plants in various conditions from living and healthy to dead and decaying. ...
... О функциональном значении этих звуковых сигналов существует мнение (Victorsson, Wikars, 1996), что, используя их, личинки жуков-усачей равномерно распределяются в древесине во избежание каннибализма. Наличие каннибализма у личинок M. sutor, изъятых из естественной среды обитания и помещенных в чашку Петри с опилками, лишенных таким образом возможности издавать сигналы, подтверждено экспериментально. ...
... Замечания. Личинки M. urussovi издавали сигналы, находясь между корой и древесиной, а не располагаясь в своем ходе перпендикулярно коре, как это указано для M. alternatus и M. sutor (Izumi et al., 1990;Victorsson, Wikars, 1996). По крайней мере, более пяти личинок M. urussovi, извлеченных нами из мест эмиссии сигнала, занимали го- ...
The territorial and warning signals of the sawyer beetle larvae Monochamus urussovi (F.-W.) (Coleoptera, Cerambycidae) are described at the first time. The characteristics of the larvae sounds pulses of the three species Monochamus sp. (USA), M. alternatus (Japan) and M. urussovi (Russia) are compared. Substantial differences of their signals are found. Oscillogramms are presented.
... The number of larvae tested on each diet was 30. Only one larva was used by Petri dish, as the individuals tend to be aggressive to each other (Victorsson and Wikars, 1996;Dodds et al., 2001). The Petri dishes were kept in rearing chambers with constant temperature and humidity (25ºC, 65% RH, 15:9 LD) until pupae were obtained (Fig.1d), being then removed from the diets and placed in a clean Petri dish with moistened filter paper. ...
The pine sawyer Monochamus galloprovincialis (Olivier, 1795) is the vector of the introduced pine
wood nematode Bursaphelenchus xylophilus (Steiner and Buhrer, 1934) in Portugal, and until recently
was considered a secondary insect pest. In this study eight artificial diets were tested with the purpose
of rearing this insect under laboratory conditions with reduced costs and high efficiency. Tested diets
included various artificial mediums commercially available for other insects and mediums based on dried
or fresh pine phloem. Among the eight tested variations, diet #5 was the most efficient with 80% eclosions
of adult beetles, while diet #6 allowed the fastest development, with the first adult emerging within 53
days. The best rearing method, the diet ingredients and the prices of the diets are discussed, resulting in
a list of essential ingredients for the artificial rearing of the pine sawyer.
... Others had one scab each. larval density and/or large size disparity, as reported in phloem-feeding cerambycids such as Monochamus sutor L. (Victorsson and Wikars 1996), M. alternatus Hope (Anbutsu and Togashi 1997), and M. carolinensis (Olivier) (Dodds et al. 2001). ...
Larval competition and allometry in the stag beetle Dorcus rectus (Motschulsky) were investigated in the laboratory and the field. Allometry indicated three larval groups Of different head capsule widths and body masses, representing three instars. A laboratory experiment, in which two larvae were placed on milled decaying wood in test tubes for two weeks, showed that cannibalism occurred in the first and second instars. Cannibals tended to have larger head capsules than their victims. Cannibalizing larvae gained more body mass than non-cannibals. The carbon/nitrogen ratio of decaying wood was much higher than that of larvae, explaining an increased body mass following cannibalism. Sixty-two percent of surviving second instars was wounded by their opponents. When cannibalism did not occur by second instars, large-headed larvae grew but the growth of small-headed larvae Was restricted, suggesting strong interference. However, a field study suggested low rates of interference competition between larvae.
... The substrate-borne vibrations produced by both species are emitted as sounds readily audible to humans from the distance of a few meters. Sound production has also been observed in two other species of the same subfamily -Monochamus alternatus Hope, 1842 [10] and M. sutor L., 1758 [8]. Both the authors established that the sound was produced by the scratching of mandibles against the beetle gallery walls. ...
... Sound production in larvae of Cerambycidae is a rare phenomenon described in only few species of lamiine longicorns (Cerambycidae: Lamiinae)8910. Larvae probably emit the sounds by the scratching of mandibles (or other specialized sclerotized structures [12,13]) against the beetle gallery walls, although Leiler [9] assumed sound production occurred by knocking of the head against the wall of larval burrow. ...
... Pulses generated by scraping of mandibles in one direction shown some distinctive patterns compared to pulses generated in the opposite direction, so each even pulse is slightly different than uneven in relation to the character of the bark surface. Victorsson and Wikars [8] suggested that Monochamus sutor larvae used sound production in territorial defense, signalling their presence to other larvae to avoid competition and cannibalism under the bark, when the food source (wood mass within the branch and especially the underbark) is limited and it can support only a limited number of beetle larvae. Saliba [14] showed that Cerambyx dux (Faldermann, 1837) larvae were able to move sharply in feeding galleries to avoid other larvae in close proximity and speculated that the more winding galleries in densely colonized regions (as compared with more straight ones where the larva worked alone) are a result of the larvae avoiding contact with each other by excavating their galleries in a direction from which no vibrations are registered. ...
Substrate-borne vibrations produced by the larvae of non-lamiinae longicorn Icosium tomentosum Lucas, 1854 (Cerambycidae: Cerambycinae) are also emitted as loud sounds audible to humans. The vibrations consists of a
long sequence of regularly repeated pulses at a rate of 8 pulses per second. The duration of the pulses are 0.061±0.009 s
and the interpulse intervals are 0.065±0.015 s. The mechanism of vibration generation is the scraping by strongly sclerotised
mandibles against the bark. Chorusing behaviour previously unknown in Cerambycidae larvae have been observed when the larvae
feeding in the same or nearby branches starting to produce the audible vibrations in reaction to the vibrations of another
larva.
... Dodds et al. (2001) reported that cannibalism occurred between larvae of M. carolinensis in artiWcial phloem sandwiches . Cannibalistic behaviour of Monochamus larvae in other species has also been reported (Anbutsu and Togashi 1997; Rose 1957; Victorsson and Wikars 1996). Togashi (1990) reported larval cannibalism in the third and fourth stage larvae of M. alternatus Hope, the Japanese vector of the pine wood nematode, in naturally infested logs. ...
The study of the life history dynamics of the pine sawyer beetle Monochamus galloprovincialis (Olivier) is important because the beetles vector the pinewood nematode. The objectives of this study were to investigate
differences in beetle life history parameters between the two common host tree species in Turkey, Pinus sylvestris and Pinus nigra. Relationships between the number of oviposition sites, holding time (time between log cut and oviposition), log moisture
content, log volume and area, and adult survivorship were evaluated. No significant differences were found between the two
tree species except adult density per m2. The holding time did not influence the number of oviposition sites, larval entry holes or adults for P. sylvestris. There was a negative correlation between the holding time and the number of oviposition sites for P. nigra. The number of adults emerged per log was correlated with the number of larval entry holes only for P. sylvestris. Only 12 and 15% of the initial cohort completed development and emerged as adults for P. sylvestris and P. nigra, respectively. Both tree species are equally suitable hosts for M. galloprovincialis development. We conclude that the high within-log mortality of beetles is a combination of resource quality and quantity
factors and intraspecific competition and cannibalism during larval development.
