Ants impact the energy reserves of natural enemies through the shared honeydew exploitation

1. Ants, as well as many species of parasitoids and predators, rely on sugar‐rich foods such as honeydew to fulfill their energetic needs. Thus, ants and natural enemies may interact through the shared honeydew exploitation. 2. Ant‐exclusion experiments were performed in a citrus orchard to test the hypothesis that ants may impact the energy reserves of predators and parasitoids through the competition for honeydew. Through the use of high‐performance liquid chromatography (HPLC) the level of ant activity with the energy reserves and feeding history of individual specimens collected in the field during representative days of spring, summer, and autumn were related. 3. Out of 145 Aphytis chrysomphali Mercet parasitoids captured in the field, 65% were classified as sugar‐fed and 24.7% as honeydew‐fed. In summer, when ant activity peaked, there was a significant negative correlation between the level of ant activity and the total sugar content and honeydew feeding incidence by A. chrysomphali. Out of 47 individuals of the predator Chrysoperla carnea sensu lato (Stephens), captured in the field, 55.3% were classified as sugar‐fed. We found a significant negative effect of the level of ant activity on the sugar‐feeding incidence by C. carnea in spring. 4. The present study provides evidence that ants can interfere with the energy reserves of natural enemies. This interaction may be widespread in various ecosystems with important consequences for the arthropod community composition and with practical implications for biological control given that absence of sugar feeding is detrimental for the fitness of many species of predators and parasitoids.     

Acromyrmex ameliae sp. n. （Hymenoptera： Formicidae）： A new social parasite of leaf-cutting ants in Brazil

The fungus-growing ants （Tribe Attini） are a New World group of〉 200 species, all obligate symbionts with a fungus they use for food. Four attine taxa are known to be social parasites of other attines. Acromyrmex （ Pseudoatta） argentina argentina and Acromyrmex （Pseudoatta） argentina platensis （parasites of Acromyrmex lundi）, and Acromyrmex sp. （a parasite of Acromyrmex rugosus） produce no worker caste. In contrast, the recently discovered Acromyrmex insinuator （a parasite of Acromyrmex echinatior） does produce workers. Here, we describe a new species, Acromyrmex ameliae, a social parasite of Acromyrmex subterraneus subterraneus and Acromyrmex subterraneus brunneus in Minas Gerais, Brasil. Like A. insinuator, it produces workers and appears to be closely related to its hosts. Similar social parasites may be fairly common in the fungus-growing ants, but overlooked due to the close resemblance between parasite and host workers.     

The survival rate of Lanyu Scops Owls Otus elegans botelensis

Few species of owls have been well studied in the wild and estimates of survival rates are available only for a few species in the temperate region. This paper reports the adult annual and monthly survival estimates of the Lanyu Scops Owl Otus elegans botelensis , a subtropical Asian species, based on a 13-year study of a colour-marked population. The estimated seasonal survival pattern was relatively stable, with an indication of lower survival during May-June, the time of egg-laying and chick-rearing. Female survival in this species was consistently higher than male survival by an estimated 7%, which may have resulted from differential costs in reproduction. Annual survival rates during 1986-96 showed no significant differences between years. Based on a model with constant survival and annual variation in recapture rate, average annual survival for all birds was estimated as 75%, which is higher than expected given the small body weight of the Lanyu Scops Owl. This survival and the stable monthly survival pattern are discussed in light of the mild subtropical conditions of Lanyu Island.     

Early Permian (Asselian) brachiopods from Karakorum (Pakistan) and their palaeobiogeographical significance

Abstract: Early Permian (Asselian) brachiopods collected from the Gircha Formation of western Karakorum (Pakistan) are described. They include Bandoproductus girchensis sp. nov., Kiangsiella sp. indet., Trigonotreta lyonsensis Archbold and Thomas, Trigonotreta larghii sp. nov., Spirelytha petaliformis (Pavlova), Punctospirifer afghanus Termier, Termier, de Lapparent and Marin, and ?Dielasma sp. indet. and belong to the Trigonotreta lyonsensis–Punctospirifer afghanus Assemblage Biozone, the oldest so far recovered from the Permian succession of Karakorum. The faunal succession of Karakorum records a significant biotic change from the Asselian to the Sakmarian, a shift in diversity and composition that is also recorded along most of the Gondwanan margin and Peri‐Gondwanan regions and that should be related to a major climatic change: the end of the Gondwanan glaciation. A palaeobiogeographical analysis has been performed by means of multivariate methods applying cluster and ordination analyses based on the Jaccard Coefficient and Simpson Index to a matrix consisting of the presence/absence of 23 brachiopod genera from seven geographical operational units from central Afghanistan to eastern Australia. The results suggest the occurrence of a single biotic province during the Asselian, the Indoralian Province, embracing all the faunal stations examined, as a consequence of the global cold phase related to the last pulse of the Gondwanan glaciation.     

SHORT COMMUNICATION Should the use of inhibition of cholinesterases as a specific biomarker for organophosphate and carbamate pesticides be questioned

Recently there has been evidence that contaminants other than organophosphate and carbamate pesticides may inhibit the activity of the enzyme acetylcholinesterase (AChE) both under in vitro and in vivo conditions. In this study we investigated the in vitro effect of three detergents \[dodecyl benzyl sulphonate (DBS), sodium dodecyl sulphate (SDS) and a mixture commonly used as domestic detergent (X)] and three metals \[molybdenum, barium and chromium (VI)] on AChE activity of Mytilus galloprovincialis haemolymph. All the detergents tested significantly inhibited the activity of the enzyme. The lowest observed effect concentrations were equal to 12 5 for DBS and 50 mg l-1 for SDS and X. Among the metals, molybdenum and barium had no effect on AChE activity, whereas chromium (VI) significantly depressed the activity of the enzyme at concentrations equal to or higher than 25 mg l-1. These results suggest that the use of AChE as a specific biomarker for organophosphate and carbamate pesticides should be questioned and that the use of this enzyme as a biomarker could be extended.     

A new species of Exostyles (Leguminosae, Papilionoideae, Swartzieae s.l.), from Paraná State, Brazil

A new species Exostyles godoyensis Soares-Silva & Mansano (Leguminosae, Papilionoideae, Swartzieae), endemic to Paraná state in southern Brazil, is described and illustrated. The new species is distinct from all the other species of Exostyles in having a leaf with up to five leaflets, while the other species have at least seven leaflets per leaf. The new species is distinct from Exostyles amazonica Yakovlev in its longer stamen filaments and ovary stipe and from E. glabra Vogel and E. venusta Schott by its shorter anthers. In addition to these morphological characters E. godoyensis has a disjunct geographical distribution.  © 2004 The Linnean Society of London, Botanical Journal of the Linnean Society , 2004, 146 , 103–106.