The longhorn beetle Cerambyx welensii is an emerging pest involved in oak decline episodes, whose damage is increasingly reported in dehesa open woodlands. Knowledge of the reproductive biology of C. welensii is a crucial goal due to its new pest status. In this study, we assess the reproductive traits of both sexes in the laboratory (25°C and 60% relative humidity ). In females, body length was 44.9 ± 0.9 mm (mean ± SE), fecundity 132 ± 12 eggs, fertility 70 ± 1 %, longevity 70 ± 3 days, preoviposition period 2 ± 0.2 days, oviposition period 44 ± 3 days and postoviposition period 19 ± 3 days. Fecundity was positively correlated with female size, longevity and oviposition period. Daily fecundity was 3.0 ± 0.2 eggs/day and showed a fluctuating synovigenic pattern with a slight decreasing trend over time. Egg length was 4.24 ± 0.01 mm and egg volume 8.14 ± 0.04 mm3. Egg size was correlated with female size but the relative size of eggs was larger in smaller females. Incubation time was 13.9 ± 0.1 days and hatching did not depend on egg size. Neonate size was positively correlated with egg length. Females were polyandrous (more than 20 lifetime matings) but multiple mating did not increase fecundity, fertility or longevity. In males, body length was 43.7 ± 0.6 mm and longevity 52 ± 3 days. Unlike with females, longevity was positively correlated with male size. Males were polygynous (up to 30 lifetime matings) but mating history did not affect male longevity. Rather to the contrary, long-lived males mated more times because they had more mating chances. Lastly, C. welensii reproductive traits were compared with those other Cerambycidae species and discussed from an adaptive perspective. Our data will be useful to improve management of C. welensii in order to prevent or mitigate its impact in dehesa woodlands and other oak forests.

Abstract. 1. Cerambyx welensii (Cw) and Cerambyx cerdo (Cc) are two large saproxylic beetles living on Quercus trees in the Western Palearctic whose current pest and legal status differs markedly. Cw is an emerging pest involved in oak decline while Cc is an internationally protected species.2. Acquiring knowledge of the ecology, demography and behaviour of Cw and Cc in forests harbouring mixed populations is a demanding task to optimise their management or protection. Here, we report the results of a mark-recapture study on the flight behaviour and dispersal potential of both species in holm oak open woodlands.3. Average flights, dispersal rates and diffusion models were remarkably similar in Cw and Cc, reflecting a low-dispersal tendency and sedentary behaviour. However, a subset of adults in both species exhibited a huge propensity to disperse and flew more than 1 km. An aggregated distribution of dispersal distances suggested that a behavioural polymorphism might underlie the flight pattern.4. Adults moved preferentially in those spatial directions with neighbouring trees, while prevailing winds did not significantly affect dispersal patterns. The main interspecific differences were as follows: (i) Cc performed longer crosswind flights than Cw on windy days; (ii) Cc tended to fly farther than Cw at low temperatures; and (iii) adult feeding improved dispersal but only in small Cw females. Moon phase did not affect flight activity.5. The results are discussed in an effort to interpret how these ecological and behavioural differences might shape the life history of both congeneric species when they live in sympatry in dehesa woodlands.

size, altitude and sun exposure. Wood quality and host preference were major factors segregating interspeciic 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.Abstract 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, signiicantly 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 km 2 ). Bolts were measured, scored into ive wood quality classes, dissected, and all target cerambycids were collected, measured, reared and taxonomically identiied. We then determined species-speciic prevalence, niche breadth, niche overlap, age structure and population density depending on wood quality, host preference, tree part, wood Electronic supplementary material The online version of this article (

No abstract

No abstract