Two methods of assessing the mortality factors affecting the larvae and pupae of Cameraria ohridella in the leaves of Aesculus hippocastanum in Switzerland and Bulgaria

The horse-chestnut leaf miner, Cameraria ohridella, is an invasive alien species defoliating horse-chestnut, a popular ornamental tree in Europe. This paper presents quantitative data on mortality factors affecting larvae and pupae of the leaf miner in Switzerland and Bulgaria, both in urban and forest environments. Two sampling methods were used and compared: a cohort method, consisting of the surveying of pre-selected mines throughout their development, and a grab sampling method, consisting of single sets of leaves collected and dissected at regular intervals. The total mortality per generation varied between 14 and 99%. Mortality was caused by a variety of factors, including parasitism, host feeding, predation by birds and arthropods, plant defence reaction, leaf senescence, intra-specific competition and inter-specific competition with a fungal disease. Significant interactions were found between mortality factors and sampling methods, countries, environments and generation. No mortality factor was dominant throughout the sites, generations and methods tested. Plant defence reactions constituted the main mortality factor for the first two larval stages, whereas predation by birds and arthropods and parasitism were more important in older larvae and pupae. Mortality caused by leaf senescence was often the dominant mortality factor in the last annual generation. The cohort method detected higher mortality rates than the grab sampling method. In particular, mortality by plant defence reaction and leaf senescence were better assessed using the cohort method, which is, therefore, recommended for life table studies on leaf miner

Dynamics of a host–parasitoid interaction clarified by modelling and DNA sequencing

Abstract It has been hypothesised that the 2-year oscillations in abundance of Xestia moths are mediated by interactions with 1-year Ophion parasitoid wasps. We tested this hypothesis by modelling a 35-year time series of Xestia and Ophion from Northern Finland. Additionally, we used DNA barcoding to ascertain the species diversity of Ophion and targeted amplicon sequencing of their gut contents to confirm their larval hosts. Modelling of the time-series data strongly supported the hypothesised host?parasitoid dynamics and that periodic occurrence of Xestia moths is mediated by Ophion. DNA barcodes revealed that Ophion included five species rather than just one while targeted amplicon sequencing verified that Ophion does parasitise Xestia. At least one Ophion species employs 1-year Syngrapha interrogationis as an alternate host, but it did not detectably affect Xestia?Ophion dynamics. We also demonstrate the previously unrecognised complexity of this system due to cryptic parasitoid diversity.peerReviewe

Phylogeny of the subfamilies of the family Braconidae (Hymenoptera: Ichneumonoidea)

A phylogenetic analysis of the subfamilies of the family Braconidae Nees, 1812 is presented. The analysis employing 96 phylogenetically informative characters was performed using the computerized parsimony programmes PAUP and Hennig86. The cladograms obtained show that the Braconidae can be divided into three major groups of subfamilies. These are a lineage comprising the mainly ectoparasitic cyclostomes and relatives, and two advanced endoparasitic groups, both apparently derived from somewhere near the endoparasitic cyclostome subfamily Rogadinae Foerster, 1862 sensu stricto. As a result of the phylogenetic analysis subfamily rank is given to the Exothecinae Foerster, 1862 (including the Hormiini Foerster, 1862), the Rhyssalinae Foerster, 1862 (including the Pambolini Marshall, 1885), the Charmontinae van Achterberg, 1979, and the Microtypinae Szépligeti, 1908. The tribes Meteorini Cresson, 1887 and Muesebeckiini Mason, 1969 are ret

Declotila, a new genus of Orgilinae (Hymenoptera: Braconidae) without occipital carina from the Australian region

Declotila gen. nov. (Braconidae: Orgilinae; type species: D. albomarginata spec, nov.) from Victoria (Australia) is described and fully illustrated