Biogeographical,ecological and morphological structure in a phylogenetic analysis of Ateleia (Swartzieae,Fabaceae) derived from combined molecular,morphological and chemical data

A phylogenetic analysis of combined morphological, chemical and ITS/5.8S sequence data reveals that species of Ateleia are often more genetically than morphologically divergent, and that species thought to be most closely related morphologically are distant relatives within the genus. Ateleia shows niche conservatism, with most species confined to seasonally dry tropical forest in Central America and the Caribbean, and fewer species in the same biome in South America. Four independent transitions to wet forests may have occurred in the genus. The estimated ages of Ateleia lineages spanning Central and South America are either older or younger than the estimated age of closure of the Isthmus of Panama. The older dates clearly suggest that over‐water dispersal is responsible for the distribution of Ateleia that includes the Caribbean Islands. © 2010 The Linnean Society of London, Botanical Journal of the Linnean Society, 2010, 162 , 39–53.     

Host location and behavioural response patterns of the parasitoid,Tachinaephagus zealandicus Ashmead (Hymenoptera: Encyrtidae), to host and host‐habitat odours

Abstract 1. To overcome the challenge of host location in patchy and complex environments, many parasitoids exploit host‐habitat derived odour cues. This study investigated the role of odour cues used during host location by the generalist parasitoid, Tachinaephagus zealandicus, a common parasitoid of Dipteran larvae found in association with decomposing carrion. 2. A Y‐tube olfactometer was used to test aspects of host searching behaviour of T. zealandicus females under different choice scenarios: combinations of host–liver complex, eaten liver, unwashed host larvae, washed host larvae, liver in six stages of decay, and control (no odour). 3. T. zealandicus females demonstrated an innate response to, and preference for, odours arising from liver substrates following interaction with the host. However, this was dependent on the stage of meat decay. Females were not attracted to liver that had never been in contact with a host, regardless of the stage of decay. There were discernible differences in parasitoid movement and behaviour under different choice scenarios. The absence of odour stimulus elicited limited movement about the olfactometer. In the presence of any odour stimuli, females were more active within the olfactometer, and when presented with two odour options T. zealandicus females demonstrate a heightened investigation response, moving across all regions of the olfactometer. 4. Knowledge of the cues that mediate host location for T. zealandicus can contribute to fields such as forensic entomology, where the presence of parasitoids on decomposing remains can be used to estimate time since death.     

Does metazooplankton regulate the ciliate community in a shallow eutrophic lake?

1. As grazers on picoplankton and nanoplankton, planktonic ciliates form an important link in pelagic food webs. Ciliate communities may be controlled by predation by metazooplankton. In eutrophic systems, however, where the number of large crustaceans is often low, the mechanisms that regulate ciliate dynamics have rarely been described. 2. We conducted an enclosure experiment with natural and screened (145 μm) summer plankton communities to investigate the effect of the small‐sized crustacean zooplankton on ciliate community structure and the microbial loop in a shallow eutrophic lake. 3. The removal of the larger fraction of crustaceans initiated a decrease in total ciliate abundance. At the community level, we observed a substantial increase in large‐sized predacious ciliates (>100 μm) and a simultaneous decrease in the abundance of smaller ciliates (<20–40 μm) that were mostly bacterivores and bacterio‐herbivores. The compositional shift in the ciliate community, however, did not cascade down to the level of bacteria and edible phytoplankton.     

Biotic resistance on the increase: native predators structure invasive zebra mussel populations

1. Abundant native predators, parasites and pathogens that switch to consuming a hyper‐successful exotic species may be able to control the invasive population. Native predators may, however, need time to adapt to feed effectively on an exotic resource. In this case, mortality on an exotic population from native predators could increase over time even without a numerical increase in the predator population. 2. We measured mortality of zebra mussels (Dreissena polymorpha) in the Hudson River both in controls open to predation and in exclosures that excluded large predators to estimate mortality of zebra mussels from large predators and other causes. 3. We found that predation by the blue crab (Callinectes sapidus), and perhaps other predators, causes high mortality on zebra mussels in the Hudson River estuary. This predation apparently led to increased mortality and altered population structure in the invader over time. 4. Long‐term data from the Hudson River suggest that components of the invaded ecosystem, like rotifers, are recovering through predator‐caused release from zebra mussel grazing. Increased mortality on hyper‐successful exotic populations over time may be a common phenomenon with both ecological and management implications.     

Using palaeolimnological and limnological data to reconstruct the recent history of European lake ecosystems: introduction

1. As future climate change is expected to have a major impact on freshwater lake ecosystems, it is important to assess the extent to which changes taking place in freshwater lakes can be attributed to the degree of climate change that has already taken place. 2. To address this issue, it is necessary to examine evidence spanning many decades by combining long‐term observational data sets and palaeolimnological records. 3. Here, we introduce a series of case studies of seven European lakes for which both long‐term data sets and sediment records are available. Most of the sites have been affected by eutrophication and are now in recovery. 4. The studies attempt to disentangle the effects of climate change from those of nutrient pollution and conclude that nutrient pollution is still the dominant factor controlling the trophic state of lakes. 5. At most sites, however, there is also evidence of climate influence related in some cases to natural variability in the climate system, and in others to the trend to higher temperatures over recent decades attributed to anthropogenic warming. 6. More generally and despite some problems, the studies indicate the value of combining limnological and palaeolimnological records in reconstructing lake history and in disentangling the changing role of different pressures on lake ecosystems.     

The Occurrence of Schellackia and Plasmodium in two Georgia Lizards

SYNOPSIS. During a 15-year survey (1956–1970) involving more than 12,000 lizards, the incidence and annual fluctuations of both Plasmodium floridense and Schellackia occidentalis are reported. The occurrence of P. floridense in Anolis carolinensis from the Mainland (Fargo, Georgia area) varied from 52% (1958) to 10% (1964) with an average of 35%, while in Sceloporus undulatus from the same area during the same period it varied from 10% (1969) to 2% (1964) with an average of about 5%. The occurrence of Schellackia and Plasmodium in both Anolis and Sceloporus from Cumberland Island, and Schellackia from Anolis from 2 other Coastal Islands (Sapelo, 2% and Seahorse, 30%) are reported for the first time. On Cumberland, the only Georgia island thus far studied, where both Anolis and Sceloporus are found together, 16% of Anolis and 13% of Sceloporus had sporozoites of Schellackia sp. in the blood, while 11% of Sceloporus and 21% of Anolis harbored P. floridense.     

A Method for Determining the Position and Size of Lateral Primordia in the Axes of Roots Without Sectioning

A procedure for staining, clearing, and mounting the axis ofa root is described which permits rapid measurement of the longitudinaland radial position and the length and diameter of each lateralprimordium therein.     

Long-term culturing of plants with aseptic roots Determination of rape root exudates

Abstract A plant culture system allowing growth of aseptic roots has been designed. One version of the system comprises vessels developed for plant root-microorganism interaction studies in series. A second version has been built for measurements of different physiological parameters of the shoot and root system during growth periods of at least 2 months. The system was tested by determining soluble organic carbon glucose and sucrose in the root exudates of rape plants (Brassica napus L.) grown for 3 weeks in the culture system. The plants were cultivated with a sterile or a non-sterile root system, or with a root system infected with Verticillium dahliae Kleb.