I. M. Duarte

Phylogenetic relationships, based on SSU rDNA sequences, among the didelphic genera of the family Trichodoridae from Portugal

A survey of virus vector trichodorid nematodes was carried out in the central and northern regions of Portugal. Morphobiometric identification showed the presence of trichodorid species previously reported from Portugal, except for Paratrichodorus porosus, which is reported for the first time in Continental Europe. Small subunit ribosomal DNA (SSU rDNA) sequences of ten different species occurring in Portugal were obtained and a phylogenetic analysis based on their alignment was performed to infer relationships among the different Portuguese trichodorid species and three non-indigenous populations (Nanidorus minor, P. allius and P. teres). The resulting phylogenetic tree is in agreement with the currently accepted classification for Trichodoridae, except for Nanidorus, which clusters together with Trichodorus species, while the genera Paratrichodorus and Trichodorus appear as two distinct groups. A better understanding of the generic groupings in the family Trichodoridae was found. Based on the new molecular analyses we herein accept Nanidorus as a valid genus.

Seven new species of Trichodorus (Diphtherophorina, Trichodoridae) from Spain, an apparent centre of speciation.

During a survey for Trichodoridae in cultivated and natural environments, mainly from southern Spain, 7 new Trichodorus species were found. Four of them, T. andalusicus n. sp., T. asturanus n. sp., T. silvestris n. sp. and T. parasilvestris n. sp., belong to the T. lusitanicus morpho-species group characterised in the male by the slightly ventrally curved spicules with a mid-blade constriction with bristles, and in the female by well developed, rounded triangular to quadrangular, vaginal sclerotised pieces. They were mainly differentiated based upon differences in body length, onchiostyle length, spicule shape and number of ventromedian cervical papillae in the male, and size and shape of the vaginal sclerotised pieces in the female. The presence of the T. lusitanicus morpho-species group with 8 species, apparently endemic to the Iberian Peninsula, could point to a recent speciation event. Additionally, 3 new species, T. onubensis n. sp., T. iliplaensis n. sp. and T. paragiennensis n. sp., more closely resembling the morpho-species group of T. sparsus, to which the Spanish species T. giennensis also belongs, were identified. They were differentiated based on body length, length of onchiostyle and position of the secretory-excretory pore and, in the male, by length and shape of the spicules and number of ventromedian cervical papillae and in the female by the vaginal sclerotised pieces. Molecular support to differentiate the new species using the D2-D3 expansion segments of 28S rDNA is also provided. In addition, a new population of T. variabilis from Greece was studied as well as T. lusitanicus type specimens, and a population of T. giennensis and T. lusitanicus were also sequenced.

How Can Global Change Affect Insect Population Dynamics in Mediterranean Ecosystems? A Case Study with Pine Shoot Beetle and Pine Processionary Moth

Many insect species are able to cause important damage in agriculture, forestry and human health due to their ability to feed on plants and animals tissues or transmit fungi and other diseases. Entomologists have long recognised that periods of atypical weather conditions, such as drought, excessive precipitation or unusually hot or cold weather, have great impact on insect development. Understanding the effects of climate on ecological processes has become increasingly important in entomological research as a result of global warming, which appears to be affecting their geographic ranges and population dynamics. In Mediterranean ecosystems, pine shoot beetle, Tomicus destruens Woll, and pine processionary moth, Thaumetopoa pityocampa (Denis & Schiff), are examples of species that origin problems to man. Tomicus destruens is a phytophagus insect responsible for several damages on maritime pine (Pinus pinaster Aiton) stands during its feeding on needles and its capacity to inoculate fungi and other decaying biotic agents. Thaumetopoea pityocampa is also responsible for damages in P. pinaster stands and can provoke strong allergic reactions due the presence of urticains hairs. Both species have a physiological response to the temperature variation, which is observed in the life cycle duration and in the mortality rate. The present study aims to highlight the effect of global change/global warming in the bioecology of those Mediterranean species and their implication in forest productivity and human health.

Pine Decay Assessment by Means of Electrical Impedance Spectroscopy

Plant diseases, such as the pinewood disease, PWD, have become a problem of economical and forestall huge proportions. These diseases, that are asymptomatic and characterized by a fast spread, have no cure developed to date. Besides, there are no technical means to diagnose the disease in situ, without causing tree damage, and help to assist the forest management. Herein is proposed a portable and non-damage system, based on electrical impedance spectroscopy, EIS, for biological applications. In fact, EIS has been proving efficacy and utility in wide range of areas. However, although commercial equipment is available, it is expensive and unfeasible for in vivo and in field applications. The developed EIS system is able to perform AC current or voltage scans, within a selectable frequency range, and its effectiveness in assessing pine decay was proven. The procedure and the results obtained for a population of 24 young pine trees (Pinus pinaster Aiton) are presented. Pine trees were kept in a controlled environment and were inoculated with the nematode (Bursaphelenchus xylophilus Nickle), that causes the PWD, and also with bark beetles (Tomicus destruens Wollaston). The obtained results may constitute a first innovative approach to the diagnosis of such types of diseases.