A cave-dwelling Iberian palpigrade (Arachnida: Palpigradi) of the Eukoenenia mirabilis group.

A new species Eukoenenia amatei sp. nov. is described on the basis of a female captured in a cave in south-eastern Spain. It is characterized by the presence of a single blade on the lateral organ and the absence of a glandular complex on sternites IV and VI. Some of these characters are shared with five other species distributed in Europe, Asia, Africa and South and Central America. The new species is remarkable for the elongation of basitarsus of leg IV which is the second longest in the E. mirabilis group. Only one other species in this group, E. indalica, has similar troglomorphic characters. In addition, formulas of palp and leg chaetotaxy are provided to facilitate species comparison.

New palpigrades (Arachnida, Eukoeneniidae) from the Iberian Peninsula.

Eighteen specimens of palpigrades captured in seven caves in the provinces of Castellon and Valencia in eastern Spain are studied. We describe and illustrate three new species and a new subspecies: Eukoenenia valencianus sp. nov., Eukoenenia montagudi sp. nov., Eukoenenia sendrai sp. nov. and Eukoenenia patrizii iberica ssp. nov. The Iberian fauna now comprises nine species that we place into two different morphological groups. The relationships between species from eastern Spain and other Mediterranean species are discussed.

Rediscovery of the troglobious palpigrade Eukoenenia draco (Peyerimhoff 1906) (Palpigradi: Eukoeneniidae), with notes on the adaptations to a cave-dwelling life.

Several females, a male, and an immature of the species Eukoenenia draco (Peyerimhoff, 1906) have been captured recently in Majorca, more than a century after its description. The male of this enigmatic species is described for the first time and the female is redescribed, with new data and figures. The level of adaptation of this species to a cave-dwelling life is discussed and compared with those of other troglobitic species of palpigrades. Comparison of E. draco draco with E. draco zariquieyi (Condé, 1951) reveals substantial differences that lead us to consider E. zariquieyi stat. nov. as a full species.

Juvenile hormone synthesis: "esterify then epoxidize" or "epoxidize then esterify"? Insights from the structural characterization of juvenile hormone acid methyltransferase.

Juvenile hormones (JHs) play key roles in regulating metamorphosis and reproduction in insects. The last two steps of JH synthesis diverge depending on the insect order. In Lepidoptera, epoxidation by a P450 monooxygenase precedes esterification by a juvenile hormone acid methyltransferase (JHAMT). In Orthoptera, Dictyoptera, Coleoptera and Diptera epoxidation follows methylation. The aim of our study was to gain insight into the structural basis of JHAMT's substrate recognition as a means to understand the divergence of these pathways. Homology modeling was used to build the structure of Aedes aegypti JHAMT. The substrate binding site was identified, as well as the residues that interact with the methyl donor (S-adenosylmethionine) and the carboxylic acid of the substrate methyl acceptors, farnesoic acid (FA) and juvenile hormone acid (JHA). To gain further insight we generated the structures of Anopheles gambiae, Bombyx mori, Drosophila melanogaster and Tribolium castaneum JHAMTs. The modeling results were compared with previous experimental studies using recombinant proteins, whole insects, corpora allata or tissue extracts. The computational study helps explain the selectivity toward the (10R)-JHA isomer and the reduced activity for palmitic and lauric acids. The analysis of our results supports the hypothesis that all insect JHAMTs are able to recognize both FA and JHA as substrates. Therefore, the order of the methylation/epoxidation reactions may be primarily imposed by the epoxidase's substrate specificity. In Lepidoptera, epoxidase might have higher affinity than JHAMT for FA, so epoxidation precedes methylation, while in most other insects there is no epoxidation of FA, but esterification of FA to form MF, followed by epoxidation to JH III.