Energy allocation during the maturation of adults in a long-lived insect: implications for dispersal and reproduction.

Energy allocation strategies have been widely documented in insects and were formalized in the context of the reproduction process by the terms 'capital breeder' and 'income breeder'. We propose here the extension of this framework to dispersal ability, with the concepts of 'capital disperser' and 'income disperser', and explore the trade-off in resource allocation between dispersal and reproduction. We hypothesized that flight capacity was sex-dependent, due to a trade-off in energy allocation between dispersal and egg production in females. We used Monochamus galloprovincialis as model organism, a long-lived beetle which is the European vector of the pine wood nematode. We estimated the flight capacity with a flight mill and used the number of mature eggs as a proxy for the investment in reproduction. We used the ratio between dry weights of the thorax and the abdomen to investigate the trade-off. The probability of flying increased with the adult weight at emergence, but was not dependent on insect age or sex. Flight distance increased with age in individuals but did not differ between sexes. It was also positively associated with energy allocation to thorax reserves, which increased with age. In females, the abdomen weight and the number of eggs also increase with age with no negative effect on flight capacity, indicating a lack of trade-off. This long-lived beetle has a complex strategy of energy allocation, being a 'capital disperser' in terms of flight ability, an 'income disperser' in terms of flight performance and an 'income breeder' in terms of egg production.

First Report of Dothistroma pini, a Recent Agent of the Dothistroma Needle Blight, on Pinus radiata in France.

Dothistroma needle blight (DNB), also known as red band needle blight, is an important fungal disease of Pinus spp. that occurs worldwide. On the basis of molecular and morphological studies of the anamorphic stage, Barnes et al. (1) showed that two closely related species were involved in DNB: Dothistroma septosporum (Dorog.) Morelet and D. pini Hulbary. D. septosporum (teleomorph: Mycosphaerella pini Rostr.) has a worldwide distribution and is reported as the species that caused past epidemics of DNB. This species is reported on more than 80 different pine species, and Pinus radiata D. Don (Monterey pine) is classified as a highly or moderately susceptible species, depending on the published sources (4). D. pini (telemorph: unknown) was initially found on needles of P. nigra J. F. Arnold collected from 1964 to 2001 in the north central United States (Minnesota, Nebraska, and Michigan). It was subsequently found in Ukraine and southwestern Russia, where it has been associated with the emergence of DNB on P. nigra subsp. pallasiana (Lamb.) Holmboe, in Hungary on P. nigra, and in Russia on P. mugo Turra (1). In France, D. pini was reported for the first time on P. nigra, and was sometimes found in association with D. septosporum on the same needles (3). Later on, a more intensive survey of DNB was launched in France and 216 stands of Pinus sp. were studied. D. septosporum and D. pini were detected in 133 and 123 stands, respectively. Both species co-occurred in 40 stands but D. pini was only found on P. nigra (subsp. laricio and austriaca) (2). Up to now, D. pini was therefore only reported on European pine species, mainly on the different allopatric subspecies belonging to the black pine complex and on one occasion on P. mugo, which belongs to the same section and subsection as P. nigra. In March 2011, typical symptoms of DNB (needles with orangey-red brown distal ends, dark red bands, and green bases; small and black fruit bodies within the bands) were observed in a 50- to 60-year old P. radiata stand of ~3 ha located in Pyrénées Atlantiques close to the Spanish border (1°36'08″ W, 43°19'51″ N). The density of pine was relatively low and patches of natural regeneration were present. Although nearly all of the trees showed DNB symptoms, less than 50% of their needles were affected by the disease. In this stand, needles showing typical DNB symptoms were randomly taken from four pines and mixed together to form a single sample for analysis. Total DNA was extracted from symptomatic needle pieces. The presence of D. pini was confirmed by a specific multiplex real-time PCR analysis using the D. pini-specific primers/probe combination DPtef-F1-/R1/-P1 (3), and by sequencing a D. pini-specific amplicon generated by another conventional PCR (3) using DPtef-F/DPtef-R primers (GenBank Accession KC853059) (3). D. septosporum was not detected in the sample. To our knowledge, this is the first report worldwide of D. pini on P. radiata, a pine species largely planted in Spain and in the Southern Hemisphere. This is also the first report of this pathogen on a non-European pine species. The original native range and the host range of D. pini remain unknown and there is currently no data about host preferences or aggressiveness on different pine species. References: (1) I. Barnes et al. For. Pathol. 41:361, 2011. (2) B. Fabre et al. Phytopathology 102:47, 2012. (3) R. Ioos et al. Phytopathology 100:105, 2010. (4) M. Watt et al. For. Ecol. Manage. 257:1505, 2009.

Is the emergence of Dothistroma needle blight of pine in France caused by the cryptic species Dothistroma pini?

Dothistroma needle blight (DNB) emerged in France in the past 15 years. This disease is induced by two closely related species: Dothistroma septosporum and D. pini. Although both species are currently present in France, only D. septosporum was reported in the past. We investigated whether a recent arrival of D. pini in France could be a cause of the DNB emergence. We analyzed herbarium specimens of pine needles with DNB symptoms using polymerase chain reaction techniques to study the past frequency of D. pini in France. We also determined the present distribution within the country of D. septosporum and D. pini and compared it with the spatial pattern of DNB reported in the Département de la Santé des Forêts (DSF; French forest health monitoring agency) database. Although D. pini was detected on herbarium specimens from 1907 and 1965, it was not frequent in France in the past. Today, it is frequent, although not present throughout the country, being absent from the north and the east. There is no relationship between the D. pini distribution in France and the spatial pattern of DNB reported in the DSF database. Thus, the emergence of DNB in France cannot be explained by a recent arrival of D. pini.