Ecological analyses to inform management targets for the culling of crown-of-thorns starfish to prevent coral decline

The crown-of-thorns starfish (COTS), Acanthaster cf. solaris, is one of the main contributors to declines in coral cover on the Great Barrier Reef (GBR) and remains one of the major acute disturbances on coral reefs throughout much of the Indo-Pacific. Extensive control programs on the GBR involve manual culling of COTS in the field, and research is needed to inform these management efforts. Data from the Great Barrier Reef Marine Park Authority’s (GBRMPA) COTS control program provide near-real-time CPUE (Catch-Per-Unit-Effort, COTS culled per minute) data ideal for operational decision-making but these must be converted to density estimates before they can be related to ecological status of reefs or incorporated into ecological models. We developed conversions between common COTS field survey methods (i.e. manta tow, SCUBA transect searches) and COTS control program CPUE data using estimates of sightability and detectability. We used a population model and COTS size-structure data from COTS control program culling efforts to estimate that, on average, only 19% of 1-yr-old COTS (1–15 cm) are available to be culled. Finally, we developed a CPUE-COTS density relationship to estimate the threshold levels of COTS that prevent net growth of hard corals. Culling programs should therefore aim to achieve CPUEs below these ecological thresholds in order to effectively promote coral growth and recovery. These ecologically sustainable thresholds of COTS density varied depending on hard coral cover. For example, for 35% fast-growing coral cover, COTS culling needs to continue until CPUE decreases to below 0.05 COTS/min (1 COTS per 20 min) in order to prevent coral decline, whereas if coral cover is higher (80%), then a higher target threshold CPUE of ca. 0.08 COTS/min (ca. 3 COTS per 40 min) may be ecologically sustainable. These estimates underpin the current pest management rules being implemented by the GBRMPA in its COTS control program.

     

Improvement in cyst recovery and molecular detection of Giardia duodenalis from stool samples

Molecular Biology Reports - Molecular detection of Giardia duodenalis by polymerase chain reaction (PCR) is difficult in faecal samples due to inhibitors that contaminate DNA preparations, or due...     

Dispersal and dormancy strategies among insect species competing for a pulsed resource

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Phylogenetic relationships of Microdontinae (Diptera: Syrphidae) based on molecular and morphological characters

The intrasubfamilial classification of Microdontinae Rondani (Diptera: Syrphidae) has been a challenge: until recently more than 300 out of more than 400 valid species names were classified in Microdon Meigen. We present phylogenetic analyses of molecular and morphological characters (both separate and combined) of Microdontinae. The morphological dataset contains 174 characters, scored for 189 taxa (9 outgroup), representing all 43 presently recognized genera and several subgenera and species groups. The molecular dataset, representing 90 ingroup species of 28 genera, comprises sequences of five partitions in total from the mitochondrial gene COI and the nuclear ribosomal genes 18S and 28S. We test the sister‐group relationship of Spheginobaccha with the other Microdontinae, attempt to elucidate phylogenetic relationships within the Microdontinae and discuss uncertainties in the classification of Microdontinae. Trees based on molecular characters alone are poorly resolved, but combined data are better resolved. Support for many deeper nodes is low, and placement of such nodes differs between parsimony and Bayesian analyses. However, Spheginobaccha is recovered as highly supported sister group in both. Both analyses agree on the early branching of Mixogaster, Schizoceratomyia, Afromicrodon and Paramicrodon. The taxonomical rank in relation to the other Syrphidae is discussed briefly. An additional analysis based on morphological characters only, including all 189 taxa, used implied weighting. A range of weighting strengths (k‐values) is applied, chosen such that values of character fit of the resulting trees are divided into regular intervals. Results of this analysis are used for discussing the phylogenetic relationships of genera unrepresented in the molecular dataset.     

Social Tolerance in Wild Female Crested Macaques (Macaca nigra) in Tangkoko‐Batuangus Nature Reserve,Sulawesi, Indonesia

In primates, females typically drive the evolution of the social system and present a wide diversity of social structures. To understand this diversity, it is necessary to document the consistency and/or flexibility of female social structures across and within species, contexts, and environments. Macaques (Macaca sp.) are an ideal taxon for such comparative study, showing both consistency and variation in their social relations. Their social styles, constituting robust sets of social traits, can be classified in four grades, from despotic to tolerant. However, tolerant species are still understudied, especially in the wild. To foster our understanding of tolerant societies and to assess the validity of the concept of social style, we studied female crested macaques, Macaca nigra, under entirely natural conditions. We assessed their degree of social tolerance by analyzing the frequency, intensity, and distribution of agonistic and affiliative behaviors, their dominance gradient, their bared‐teeth display, and their level of conciliatory tendency. We also analyzed previously undocumented behavioral patterns in grade 4 macaques: reaction upon approach and distribution of affiliative behavior across partners. We compared the observed patterns to data from other populations of grade 4 macaques and from species of other grades. Overall, female crested macaques expressed a tolerant social style, with low intensity, frequently bidirectional, and reconciled conflicts. Dominance asymmetry was moderate, associated with an affiliative bared‐teeth display. Females greatly tolerated one another in close proximity. The observed patterns matched the profile of other tolerant macaques and were outside the range of patterns of more despotic species. This study is the first comprehensive analysis of females’ social behavior in a tolerant macaque species under natural conditions and as such, contributes to a better understanding of macaque societies. It also highlights the relevance of the social style concept in the assessment of the degree of tolerance/despotism in social systems. Am. J. Primatol. 75:361‐375, 2013. © 2013 Wiley Periodicals, Inc.     

Effects of different thermal treatments during embryonic development on the artificial incubation efficiency of crayfish (Austropotamobius pallipes Lereboullet) eggs. Control of the embryogenetic duration and implications for commercial production

Summary

The development and improvement of artificial incubation techniques for freshwater crayfish eggs and their incorporation into the working schedule of breeding centres is of great interest for commercial production. Factors such as the water circulation system, flow rate, thermal treatment, etc., could strongly influence the success of the process. The present study attempts to test the possible influence of one of these variables, the thermal regime, on both the duration of embryonic development and the efficiency rates obtained in the artificial incubation of white-clawed crayfish (Austropotamobius pallipes) eggs. Four different thermal treatments were tested (three of them included a period at low temperature: 4°-5°C). Survival rates to juvenile stage 2 were similar in the four cases, ranging between 66.7 and 72.7%. We conclude that water cooling (an expensive management procedure) is not necessary in astacid breeding centres provided that egg development takes place at moderately low temperatures (8°-10°C) with a subsequent increase of up to 15°C from the eyed stage. However, the inclusion of periods at low temperature (4°-5°C) allows the staggered production of juvenile batches throughout a 3-week period without adverse effects on efficiency rates. This could be useful to breeding centres in meeting seasonal market requirements. In our study, egg and juvenile losses (mortality rate: 15–20%) were concentrated during the last phases of embryogenesis, particularly from the eyed stage to juvenile stage 2, during which they amounted to more than 90% of the overall mortality which took place during the artificial incubation process.     

Ultrastructural study of metamorphosis in the freshwater bryozoan Plumatella fungosa (Bryozoa,Phylactolaemata)

Summary

At metamorphosis the attachment of the Plumatella larva to the substrate is effected by secretions from glandular cells in the apical plate, the leading pole during swimming. The larval mantle folds back and slides down towards the substrate. By ciliary activity an adhesive secretion is spread over the metamorphosing larva and the attachment area. Two polypides appear through the larval terminal opening. The mantle fold, together with gland cells, nerve cells, sensory cells, and muscle cells from the larva form a nutritive cell mass. Reduction of this nutritive cell mass is accomplished by autolysis and phagocytosis. An invaginated area of the nutritive cell mass is provided with a dense layer of microvilli, which seem to have an absorbtive function. The nutritive cell mass consisting of transitory larval tissues provides a significant source of nutrient for the developing polypide buds.     

Wolbachia endosymbiont in a species of the Anastrepha fraterculus complex (Diptera: Tephritidae)

Summary

In Anastrepha sp.2 aff. fraterculus, the egg-cell harbours a large population of endosymbionts. The bacteria were identified as belonging to genus Wolbachia by PCR assay using primers of the ftsZ gene followed by sequencing of the amplified band. Newly deposited eggs stained in toto by Hoechst show that the bacteria are unevenly dispersed throughout the egg-cell, with a higher accumulation at the posterior pole, and that the degree of infestation varies from egg to egg. Analysis by transmission electron microscopy shows that bacteria are present in the female germ line of embryonic and larval stages, as well as in the different cell types of the ovaries at the adult stage. Mature ova within the follicles harbour a large population of the symbionts. The results indicate the existence of a transovarian transmission of the endosymbionts in this fly.     

Evaluation of the larvicide effect of an aqueous extract of Persea americana (Miller, 1768), Lauraceae,on Anopheles gambine (Giles, 1902), Diptera Culicidae

Summary

In-laboratory evaluation of the larvicide effect of an aqueous extract of Persea americana (Miller 1768) on the various larval stages of Anopheles gambiae (Giles 1902) has shown that larvae at all stages are sensitive to this extract. Inversely proportional to the larval stage, their sensitivity proved to depend on the level of concentration: the higher the latter, the higher the former. Indeed, after a 24-h exposure, concentrations of 510 μg/ml resulted in the death of 100% of larvae at stages 1 and 2, whereas for the same time of exposure there was need to resort to concentrations of 850 μg/ml to kill them at stages 3 and 4. The aqueous extract of Persea americana has therefore a poisonous effect on larvae of Anopheles gambiae. This extract has direct lethal effects and acts as an inhibitor of larval development at sublethal concentration levels.     

Spermatogenesis and sperm—spermatheca relations in Spirorbis spirorbis (L.)

The differentiation from early spermatid to spermatozoon is described with special emphasis on the formation of the helix of chromatin and mitochondrial junctions. The role of microtubules in morphogenesis is discussed.

New observations on the role of the recently described spermatheca are presented; phagocytosis and digestion of spermatozoa are proven, and the various origins of the sperm found in the spermatheca are specified.