Host specificity ofAcanthoscelides quadridentatus andA. Puniceus [Col.: Bruchidae] for biological control ofMimosa pigra (with preliminary data on their biology)

The biology and host specificity of the seed-feeding bruchids,Acanthoscelides quadridentatus (Schaeffer) andA. puniceus Johnson, from Mexico were studied in quarantine facilities in Australia. Distinguishing characters in the genitalia of each species are illustrated. Oviposition was recorded on 16 of 73 species of plants tested but larvae died without entering pods or seeds, except onMimosa invisa K. F. P. von Martius andM. pigra L. Larvae entering seeds ofM. invisa died in the first instar. The bruchids were clearly specific toM. pigra and were subsequently released as part of a program for biological control of this weed in the Northern Territory, Australia in April 1983 and thailand in July 1984.      

Absence of plasma membrane H+-ATPase in plasmodesmata located in pit-fields of the young reactive pulvinus ofMimosa pudica L.

Summary Immunocytochemical techniques were employed to study the spatial distribution of the plasma membrane H⁺-ATPase within various cell types of the young reactive primary pulvinus ofMimosa pudica L. These cells were interconnected by large numbers of plasmodesmata, being concentrated within pit-fields. Although we could routinely detect evidence of the H⁺-ATPase along the plasma membrane, immunolabelling was rarely, if ever, observed along the plasma membranes of the plasmodesmata. This finding is discussed with respect to the likely specialized supramolecular structure of the plasmodesma.Abbreviations SEL size exclusion limit of plasmodesmata     

Oviposition and feeding preferences of a flower-feeding weevil,Coelocephalapion aculeatum, in relation to conspecific damage to its host-plant

The oviposition and feeding preferences ofCoelocephalapion aculeatum Fall (Coleoptera: Apionidae), a host specific florivore ofMimosa pigra L. (Mimosaceae), were studied in relation to conspecific damage to its hostplant. Adults ofC. aculeatum cease ovipositing in inflorescences when the egg load reaches a number consistent with the larval carrying capacity of the inflorescence. The basis for this oviposition deterrence was examined by offering inflorescences damaged by adult feeding alone, larval feeding alone and a combination of adult feeding and oviposition. Adults preferred to oviposit on inflorescences which are not damaged by either adult feeding, larval feeding, or oviposition. No evidence for the existence of an oviposition deterring pheromone (ODP) was found. I suggest that the ability of a single host inflorescence to support the development of many larvae causes selection for the use of these oviposition deterring cues which can convey more quantitative information about the level of previous infestation than can ODPs. Adults fed a similar amount on damaged compared to undamaged inflorescences. These results assisted in the design of host range testing trials and allows predictions to be made about the effectiveness of this insect as a biological control agent.     

The shortening and action potential of the cortex in the main pulvinus ofMimosa pudica

The shortening and action potential of the upper and lower cortices of the main pulvinus ofMimosa pudica were recorded simultaneously. The shortening and action potential were observed only in the lower cortex. The extensibility and the excitability of the cortex are discussed.     

Mimosa pigra in eastern and southern Africa: Distribution and socio‐ecological impacts

The semiaquatic weed Mimosa pigra has negative impacts on biodiversity, fishing, crop and livestock production, and tourism in most places where it has been introduced, established and proliferated. Many of the ecological impacts are well known, but its impacts on rural livelihoods are less well documented, especially in Africa. We mapped the distribution of M. pigra in eastern and southern Africa, and then compared that with its potential distribution based on an ecoclimatic niche model. Household interviews were conducted to assess the impacts of this weed on local livelihoods. Mimosa pigra was found to be invasive in western Ethiopia, around the shores of Lake Victoria and Lake Tanganyika, and along the Tanzanian coastline, northern Malawi, parts of Mozambique and along the Kafue River and in the Barotse floodplain on the Zambezi River in Zambia. According to respondents living along the Kafue River floodplains in Zambia, it has a negative impact on biodiversity, wildlife, livestock, crop production, fishing and mobility. Dense stands prevented the movement of people and livestock, limiting access to croplands, grazing lands and fishing areas. Fish catches have been reduced and fishing equipment damaged. All respondents agreed that their livelihood options would be considerably enhanced if M. pigra was removed from the landscape. Based on its current and potential impact, we therefore recommend that an integrated management plan be developed and implemented, including the appropriate use of biological control agents to reduce the negative impacts of the weed.     

Biology,natural history and temporal fluctuation of the geometrid Oospila pallidaria associated with host plant phenology

We investigated the temporal fluctuation of the geometrid moth Oospila pallidaria and related it to the leaf flush season of its host plant, Mimosa setosa, and to environmental factors. Aspects of the natural history of adults are also described. Mimosa setosa produced leaves all year round, but abundance of O. pallidaria larvae in the field was seasonal. The abundance of immatures showed a tendency to decrease with rainfall and temperature. Our study is pioneering in that it provides insights into factors related to the occurrence of O. pallidaria in natural areas. In addition, the biology of immatures is provided.     

Study of the Geometry and Folding Pattern of Leaves of Mimosa pudica

Many structural and functional properties possessed by plants have great potentials to stimulate new concepts and inno-vative ideas in the field of biomimetic engineering. The key inputs from biology can be used for creation of efficient and op-timized structures. The study of the geometry and folding pattern of leaves of Mimosa pudica,referred as Sensitive Plant,reveals some of the peculiar characteristics during folding and unfolding. When the leaf is touched,it quickly folds its leaflets and pinnae and droops downward at the petiole attachment. With the help of experiments on simulation model,the variations in angle of leaflets and degree of compaction after folding are investigated.     

Observed case of infanticide committed by a resident male central American black howler monkey (Alouatta pigra)

Although infanticide has been witnessed in other species of howler monkey, and has been inferred for Alouatta pigra, an observed case of infanticide has not previously been recorded for this species. Here we describe the killing of a 2-week-old infant by the resident male of a small social group in southern Belize. The infanticide was witnessed as part of an intensive observational study that began in January 2003. The male was known to have resided in the group for at least 4 months, but it is not known whether he was the father of the infant. The literature proposes three main explanations for infanticide: two adaptive hypotheses (sexual selection and resource competition), and one nonadaptive hypothesis (social pathology). Individual cases of infanticide such as this one are important for comparative purposes, but when examined on their own they are difficult to interpret in relation to established theoretical frameworks. The data presented here show some consistency with the sexual-selection and resource-competition hypotheses, but the lack of critical information (i.e., as to paternity) makes it impossible to draw firm conclusions.     

Headshields of ephippial Chydorus piger Sars (Cladocera, Chydoridae) females from northern Finnish Lapland: a long period of gamogenesis?

Numerous headshields of ephippial Chydorus piger (currently called Paralona pigra) females were found from the Holocene sediments of Aitajärvi Lake, northern Finnish Lapland (69° 08′ N, 27° 14′ E). Headshields of ephippial females of the genus Chydorus s.l. can be easily identified since their posterior margin is elongated and pointed. According to analysis of fossil cladoceran remains, Chydorus piger lived in the lake throughout the Holocene but was never very common (less than 10% of preserved cladoceran remains). Headshields of ephippial females were found in most samples and they comprised ca 10–30% of all Chydorus piger headshields. No similar phenomenon was met in Chydorus cf. sphaericus which is common up to the most severe arctic conditions. Aitajärvi is situated north of the modern distribution area of Chydorus piger. I suggest that this species reacted to the stress of harsh climatic conditions outside of its distribution area by being gamogenetic during most of the ice-free period. The ephippial headshields could be valuable indicators of severe climatic conditions in pre-Holocene sedimentary environments.     

Burkholderia species are ancient symbionts of legumes

Burkholderia has only recently been recognized as a potential nitrogen-fixing symbiont of legumes, but we find that the origins of symbiosis in Burkholderia are much deeper than previously suspected. We sampled 143 symbionts from 47 native species of Mimosa across 1800 km in central Brazil and found that 98% were Burkholderia . Gene sequences defined seven distinct and divergent species complexes within the genus Burkholderia . The symbiosis-related genes formed deep Burkholderia -specific clades, each specific to a species complex, implying that these genes diverged over a long period within Burkholderia without substantial horizontal gene transfer between species complexes.