A field evaluation of Bacillus thuringiensis var. israelensis as a biological control agent for Simulium chutteri (Diptera: Nematocera) in the middle Orange River

Bacillus thuringiensis Berliner var. israelensis de Barjac (Serotype H-14) (B.t.i.) at a concentration of 1,6 ppm/10 min and a toxicity of 1500 AAU/mg was tested against Simulium chutteri Lewis larvae in the Orange River near Prieska, South Africa. Samples of benthic fauna from the stones-in-current biotope were collected before application of the product and at various intervals up to 80 h afterwards at 4 stations from 200 m to 11 km downstream of the application site. Faunal drift increased slightly after the arrival of the Bacillus at 2 stations 1,4 and 6 km respectively downstream of the application site. Large numerical decreases in benthic simuliid larval numbers after the application of B.t.i. in the Orange River were not statistically different (P>0,05). This indicated that the size of replicated samples that showed significant decreases (P<0,05) of simuliid numbers in the Vaal River was not adequate to show statistical differences in the Orange River. The quantity of dead larvae on stones collected from rapids after application of the B.t.i., and the numerical decreases found by comparing median values of larval counts on stones indicated that B.t.i. effectively killed simuliid larvae. Three days after application of the Bacillus, recruitment of small simuliid larvae on stones 1,4 km downstream of the application site was discernible again. Tanytarsini were also numerically reduced after B.t.i. application. At a flow rate of 38 m³/s B.t.i. was visibly effective in killing S. chutteri up to 6 km downstream of the application site and statistically significant decreases (P<0,05) in numbers of larvae were seen at a site 11 km downstream of the application site. The use of B.t.i. in Simulium control is preferable to organophosphate and organochloride formulations because it has a more specific action against blackfly and because there is no known immunity to B.t.i. in any Simulium species. However, we must advise that B.t.i. should be screened against all co-existing fauna in each situation where new community structures of animals are encountered. Several methods for improving the efficacy of B.t.i. are suggested.The articles have been scanned in colour with a HP Scanjet 5590; 600dpi. Adobe Acrobat XI Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-format.mn201

The response of Vaal River drift and benthos to Simulium (Diptera: Nematocera) control using Bacillus thuringiensis var. israelensis (H-14)

Two trials. to test the efficacy of Bacillus thuringiensis Berliner var. israelensis de Barjac (serotype H-14) against target simuliid and non-target aquatic invertebrates were undertaken in the Vaal River near Warrenton in South Africa. In the 1st trail an application of 1,6 ppm/10 min of B. thuringiensis resulted in a significant (P0,05). Within 43 minutes after treatment of the rapids with the larvicide, simuliid drift increased more than sixtyfold, revealing the immediate irritating effect of the product on the target organisms. Drift of other non-target organisms was not noticeably influenced. Populations of Simulium adersi Pomeroy, S. chutteri Lewis, S. hargreavesi Gibbins, S. mcmahoni de Meillon. and S. damnosum s.l. Theobald were all significantly reduced (P<0,05) after treatment of rapids with B. thuringiensis, but S. damnosum s.l. showed the lowest mortality and appeared less affected by the product than the other species.The articles have been scanned in colour with a HP Scanjet 5590; 600dpi. Adobe Acrobat XI Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-format.am201

Book Reviews

Book Review 1Book Title: Reproductive Energetics in MammalsBook Authors: A.S.I. Loudon &amp; P.A. Racey (Eds.)Zoological Society of London Symposia 57, 1987 Clarendon. Press, Oxford. 371 pp.Book Review 2Book Title: Classification of Southern African MammalsBook Authors: J.A.J. Meester, I.L. Rautenbach, N.J. Dippenaar &amp; C.M. BakerTransvaal Museum Monograph No.5. 359 pp.Book Review 3Book Title: Pesticide impact on stream fauna with special reference to macroinvertebratesBook Author: R.C. Muirhead-ThomsonCambridge University Press, 1987. 275 pp.Book Review 4Book Title: Evolution of sex determining mechanismsBook Author: James J. BullBenjamin-Cummings Publ. Company / Addison-Wesley Publishing Group, JohannesburgBook Review 5Book Title: The evolutionary ecology of ant-plant mutualismsBook Author: Andrew J. BeattieCambridge University Press 182 pp.Book Review 6Book Title: The Ecology of SexBook Authors: P.J. Greenwood &amp; J. Adams Edward Arnold, London, 1987. 74 pagesBook Review 7Book Title: The Dinosaur Heresies - a revolutionary view of dinosaursBook Author: Robert BakkerPublished by Longman Scientific and Technical, 1987Book Review 8Book Title: Molecular Biology of the GeneBook Authors: Watson, Hopkins, Roberts, Steitz &amp; WeinerVolumes I and II (Fourth Edition) (Benjamin/Cummings. Menlo Park); Addison-Wesley Publishing Group. Johannesburg 1163 pp.Book Review 9Book Title: Evolutionary BiologyBook Author: Eli C. MinkoffAddison-Wesley Publishing Company, Massachussets, 1983. 627pp.Book Review 10Book Title: An ecosystem approach to aquatic ecology. Mirror Lake and its environmentBook Author: Gene E. Likens (Ed.)Springer-Ver1ag, New York. xiv - 516 pages; 197 figuresBook Review 11Book Title: The Physiological Ecology of SeaweedsBook Authors: C.S. Lobban, P.J. Harrison &amp; M.J. Duncan Cambridge University press, Cambridge, 1985. 242 pagesBook Review 12Book Title: Principles of ecologyBook Authors: R.J.Putman &amp; S.D. WrattenCroom Helm, London, 1984. 388 pages

Immediate impact of piscicide operations on a Cape Floristic Region aquatic insect assemblage - a lesser of two evils?

Journal of Insect ConservationThe piscicide rotenone is used as a conservation tool to remove alien fishes from rivers, though there is controversy over its effects on aquatic insects. An alien fish removal operation in the Rondegat River, Cape Floristic Region, South Africa, allowed the immediate impact of rotenone on an aquatic insect community in a region with high conservation values to be quantified. The insect community within the treated river was sampled in February 2011 (1 year before rotenone operations), February 2012 (1 week before) and March 2012 (1 week after). Insects were collected using kick sampling across multiple biotopes, together with samples from individual stones. We considered rotenone-precipitated losses to be those taxa captured a week before treatment but absent after, and assessed the endemism of lost species to determine the conservation impact of the rotenone. Species richness decreased significantly following treatment, even though many rare taxa were not recorded immediately prior to treatment. Of the 85 taxa identified, 18 were lost including five endemic to the mountain range which the river drains. Ephemeroptera were most severely affected, with a significant loss of density on stones post-rotenone and six out of 20 species missing. Since half the missing taxa were recorded upstream of the treatment area, recovery of diversity is likely to be relatively rapid. Given that alien invasive fish negatively affect both fish and aquatic insect communities in South Africa, the long-term positive conservation impact of removing these fish is likely to outweigh the short-term negative effects of the piscicide.Water Research Commission National Research Foundatio

Spatio-Temporal Dynamics of Caddisflies in Streams of Southern Western Ghats

The dynamics of physico-chemical factors and their effects on caddisfly communities were examined in 29 streams of southern Western Ghats. Monthly samples were collected from the Thadaganachiamman stream of Sirumalai Hills, Tamil Nadu from May 2006 to April 2007. Southwest and northeast monsoons favored the existence of caddisfly population in streams. A total of 20 caddisfly taxa were collected from 29 streams of southern Western Ghats. Hydropsyche (Trichoptera: Hydropsychidae) were more widely distributed throughout sampling sites than were the other taxa. Canonical correspondence analysis showed that elevation was a major variable and pH, stream order, and stream substrates were minor variables affecting taxa richness. These results suggested that habitat heterogeneity and seasonal changes were stronger predictors of caddisfly assemblages than large-scale patterns in landscape diversity

Food and feeding habits of Oreochromis mossambicus (Peters) in hypertrophic Hartbeespoort Dam, South Africa

The diet of 745 Oreochromis mossambicus (Peters) of less than 0,5 up to 2000 g wet mass, in Hartbeespoort Dam, was determined from stomach content analysis. Samples of fish were selected to cover a whole annual cycle. Small fish fed initially on zoobenthos and zooplankton, but fish with a mass of over 4 g fed increasingly on Microcystis aeruginosa Kützing and detritus until these food items formed the dominant food source in O. mossambicus over 8 g. Some cannibalism was encountered in fish up to 64 g in the summer months. The ratio of intestinal length to total length of fish ranged from 0,58 in the smaller fish to 11,02 in larger fish and this indicated that there was an ontogenetic adaptation from a carnivorous to a phytoplanktivorous /detritivorous diet. Feeding in juvenile fish studied over 24 h was found to be most intense in the early morning and late afternoon but remained high throughout daylight hours decreasing considerably at night. The daily ingestion rate of food in O. mossambicus in Hartbeespoort Dam was estimated at 453 mg/g of fish. This comprised 45% M. aeruginosa and 55% detritus. It was apparent that of this matter ingested only a small percentage would be assimilated. Oreochromis mossambicus shows feeding and breeding preadaptations which enable it to successfully exploit a lacustrine environment. These adaptations enable it to maintain a large population in Hartbeespoort Dam despite frequent winter mortalities caused by water temperatures below their tolerance limits

Weakened Resilience in Parenting Self-Efficacy in Pregnant Women Who Were Abused in Childhood: An Experimental Test

This study tested experimentally whether the combination of a history of childhood abuse and confrontation with difficult infant temperament is associated with negative changes in parenting self-efficacy. First-time pregnant women (N = 243) participated in the Adult Attachment Interview, which was used to assess the occurrence of abuse by parents in childhood and unresolved representations, and completed a task asking them to respond to infant cries. Sixty of the 243 participants (25%) experienced childhood abuse, mostly physical or sexual. The task simulated infant temperamental difficulty by manipulating soothing success in order to reflect an easy-to-soothe (80% soothing success) and a difficult-tosoothe infant (20% soothing success). Both after baseline and after each of the two stimulus series women assessed their parenting self-efficacy. Women who reported childhood abuse did not differ from women who reported no childhood abuse in parenting self-efficacy at baseline or in response to the easy-to-soothe infant (relative to baseline), but decreased more in parenting self-efficacy following the difficult-to-soothe infant. Effects did not vary according to resolution of trauma. These findings suggest that in response to infant temperamental difficulty, women who experienced childhood abuse may more easily lose confidence in their parenting abilities, which underlines the importance of preparing at-risk women for the possible challenges that come along with parenthood

Generations²: Weakened Resilience in Parenting Self-Efficacy in Pregnant Women who were Abused in Childhood: An Experimental Test

This dataset presents statistical data for an experimental study in which we tested whether the combination of a history of childhood abuse and confrontation with difficult infant temperament is associated with negative changes in parenting self-efficacy. First-time pregnant women (N = 243) reported on the occurrence of abuse in childhood and completed a task in which they were asked to respond to infant cry sounds. During this task women filled out their parenting self-efficacy after a baseline measure, after an easy-to-soothe infant (baby 1) and after a difficult-to-soothe infant (baby 2). The dataset contains information with respect to abuse experiences (yes/no and resolved/unresolved) and parenting self-efficacy measures (baseline, baby 1, and baby 2). Results showed that women who reported childhood abuse did not differ from women who reported no childhood abuse in parenting self-efficacy at baseline or in response to the easy-to-soothe infant (relative to baseline), but decreased more in parenting self-efficacy following the difficult-to-soothe infant. Effects did not vary according to resolution of trauma