Analysis of Prinobius myardi Mulsant population dynamics in a Mediterranean cork oak stand

Abstract

Abstract. The dehesa is a silvopastoral system of a high economic and ecological signifi cance in the Iberian Peninsula that is protected under the EEC/92/43 Habitat Directive. One of the most serious problems the dehesa system is currently facing is oak decline. This tree decay process is largely caused by three xylophagous cerambycids of which Prinobius myardi is the least known. In this study, we used a capture-mark-recapture method to identify the models best fi tting the behaviour of this species with a view to estimating basic population parameters such as survival rate (phi), recapture rate (p) and transiency index (T). Prinobius myardi adults were captured by hand following visual detection in the trees of a cork oak (Quercus suber) plot located in the close vicinity of the Doñana National Park (SW Spain). Males exhibited a constant survival rate exceeding 85.4% throughout their fl ight period, a maximum transiency index of 1.82% and a recapture rate ranging from 42.50% to 76.90%. These results are suggestive of a sedentary behaviour in P. myardi males. By contrast, the small number of females captured precluded calculation of the previous parameters for this gender; in any case, fi eld observations revealed a fl eeing, less sedentary behaviour with respect to the males.Résumé. Analyse de la dynamique de population de Prinobius myardi Mulsant dans un peuplement de chêne-liège. La dehesa est un système sylvopastoral de grande importance économique et écologique pour la Péninsule Ibérique. Elle est protégée par la directive «Habitat» EEC/9243. Un des problèmes les plus sérieux qui menace le système de la dehesa est le déclin du chêne-liège (Quercus suber). Ce processus de dégradation de cet arbre est largement dû à trois cérambycides parmi lesquels Prinobius myardi est le moins connu. Dans cette étude, nous avons utilisé une méthode de capture-marquage-recapture pour identifi er le modèle qui s'adapte le mieux au mode de vie de cette espèce. Dans ce but, on a estimé les paramètres de base comme le taux de survie (phi), le taux de recapture (p) et l'index de transition (T). Les Prinobius myardi adultes ont été capturés à la main, après une détection à vue, dans des placeaux de chêne-liège au voisinage du Parc National de la Doñana (SW Espagne). Les mâles ont présenté un taux de survie constant qui dépasse 85,4% tout au long de leur période de vol, un index de transition maximal de 1,82% et un taux de recapture de 42,5 à 76,90%. Ces résultats suggèrent un mode de vie sédentaire chez les mâles de P. myardi. Par contraste, le faible nombre de femelles capturées empèche de calcul de ces paramètres pour ce sexe. De toute façon, les observations montrent qu'elles sont moins sédentaires que les mâles au cours de leur période de vol.

Antennal response of Prinobius myardi to synthetic tree volatiles

“…Insects (3.8 ± 0.4 cm long, 1.2 ± 0.3 g weight; on average) were kept in individual containers with access to a 4% sugar solution, in semi-darkness (at 23-32 °C). Notably, P. myardi females were difficult to capture (the average female:male capture ratio being 0.28 over eight years (López-Pantoja et al 2011)), and most of those collected died within 24 hours.…”

“…As they colonize weakened trees, they act as an aggravating factor, hindering tree recovery (López-Pantoja et al 2011). Mediterranean Quercus ilex L. and Quercus suber L. dehesa open woodlands of the Andalucía region (Southern Spain) have high ecological, economic and cultural importance.…”

“…Mediterranean Quercus ilex L. and Quercus suber L. dehesa open woodlands of the Andalucía region (Southern Spain) have high ecological, economic and cultural importance. Hence, problems affecting stands of these species, including invasion by wood-boring beetles such as Prinobius myardi Mulsant (Coleoptera, Cerambycidae), deserve particular attention especially in a context of climate change (López-Pantoja et al 2011;Sallé et al 2014).…”

“…Prinobius myardi is a large (up to 60 mm long), holomediterranean species with nocturnal habits, whose larvae bore into wood of several deciduous tree species, especially weakened cork and holm oaks, causing tree branches and trunks to break (López-Pantoja et al 2011). In addition, these insects facilitate infection by both plant pathogens and wood-decaying fungi (Martin et al 2005).…”

“…In addition, these insects facilitate infection by both plant pathogens and wood-decaying fungi (Martin et al 2005). Despite these effects, several aspects of the behavior of P. myardi are not well known, in particular, regarding its role in oak decline, host selection cues and the development of control methods (López-Pantoja et al 2011;Torres-Vila et al 2013).…”