Murderous plants: Victorian Gothic,Darwin and modern insights into vegetable carnivory

Darwin's interest in carnivorous plants was in keeping with the Victorian fascination with Gothic horrors, and his experiments on them were many and varied, ranging from what appears to be idle curiosity (e.g. what will happen if I place a human hair on a Drosera leaf?) to detailed investigations of mechanisms. Mechanisms for capture and digestion of prey vary greatly among the six (or more) lineages of flowering plants that have well‐developed carnivory, and some are much more active than others. Passive carnivory is common in some groups, and one, Roridula (Roridulaceae) from southern Africa, is so passively carnivorous that it requires the presence of an insect intermediate to derive any benefit from prey trapped on its leaves. Other groups not generally considered to be carnivores, such as Stylidium (Stylidiaceae), some species of Potentilla (Rosaceae), Proboscidea (Martyniaceae) and Geranium (Geraniaceae), that have been demonstrated to both produce digestive enzymes on their epidermal surfaces and be capable of absorbing the products, are putatively just as ‘carnivorous’ as Roridula. There is no clear way to discriminate between cases of passive and active carnivory and between non‐carnivorous and carnivorous plants – all intermediates exist. Here, we document the various angiosperm clades in which carnivory has evolved and the degree to which these plants have become ‘complete carnivores’. We also discuss the problems with definition of the terms used to describe carnivorous plants. © 2009 The Linnean Society of London, Botanical Journal of the Linnean Society, 2009, 161 , 329–356.     

Endemic evolutionary radiation of Rhagada land snails (Pulmonata: Camaenidae) in a continental archipelago in northern Western Australia

In the Dampier Archipelago of Western Australia's Pilbara Region, several locally endemic, morphologically distinctive species of Rhagada land snails occur, contrasting with the morphologically conservative species with wider distributions on the adjacent mainland. To test alternative origins of this unusual local diversity in a continental archipelago, we examined sequences of the cytochrome oxidase subunit 1 and 16S mitochondrial genes in 22 described species and eight undescribed forms, including all known morphospecies from the Pilbara Region's Dampier Archipelago and adjacent mainland. Phylogenetic analyses consistently resolved four, deep clades within the Pilbara Region, with a mean sequence divergence of 15–18%. All but one of the species from the Dampier Archipelago formed one of the major clades, indicating that the morphological radiation in the archipelago evolved locally, rather than through multiple, relictual mainland lineages. Morphological divergence spanning almost that of the entire genus was within a subclade with sequence divergence < 4%, highlighting the disconnection between morphological diversification and levels of molecular genetic divergence. This in situ morphological radiation in the Dampier Archipelago, which transcends variation seen over much larger distances on the mainland, is unusual for a continental archipelago, and may relate to local heterogeneity of land forms. © 2012 The Linnean Society of London, Biological Journal of the Linnean Society, 2012, 106 , 316–327.     

Nucleoside diphosphate kinase from lily pollen

Nucleoside diphosphate kinase was a predominantly soluble enzymein lily pollen (Lilium longiflorum, var. Ace), and very littleenzyme activity was associated with the mitochondrial fraction.GTP was the preferred substrate when ADP was the second substrate.The enzyme was purified 18-fold to a specific activity of 7µmoles/min/mg protein. ¹This study was supported by grant GB-8764 from the U.S. NationalScience Foundation. (Received October 5, 1970; )     

Soil-surface carbon dioxide efflux and microbial biomass in relation to tree density 13 years after a stand replacing fire in a lodgepole pine ecosystem

The effects of fire on soil‐surface carbon dioxide (CO₂) efflux, F_S, and microbial biomass carbon, C_mic, were studied in a wildland setting by examining 13‐year‐old postfire stands of lodgepole pine differing in tree density (< 500 to > 500 000 trees ha^?1) in Yellowstone National Park (YNP). In addition, young stands were compared to mature lodgepole pine stands (～110‐year‐old) in order to estimate ecosystem recovery 13 years after a stand replacing fire. Growing season F_S increased with tree density in young stands (1.0 µmol CO₂ m^?2 s^?1 in low‐density stands, 1.8 µmol CO₂ m^?2 s^?1 in moderate‐density stands and 2.1 µmol CO₂ m^?2 s^?1 in high‐density stands) and with stand age (2.7 µmol CO₂ m^?2 s^?1 in mature stands). Microbial biomass carbon in young stands did not differ with tree density and ranged from 0.2 to 0.5 mg C g^?1 dry soil over the growing season; C_mic was significantly greater in mature stands (0.5–0.8 mg C g^?1 dry soil). Soil‐surface CO₂ efflux in young stands was correlated with biotic variables (above‐ground, below‐ground and microbial biomass), but not with abiotic variables (litter and mineral soil C and N content, bulk density and soil texture). Microbial biomass carbon was correlated with below‐ground plant biomass and not with soil carbon and nitrogen, indicating that plant activity controls not only root respiration, but C_mic pools and overall F_S rates as well. These findings support recent studies that have demonstrated the prevailing importance of plants in controlling rates of F_S and suggest that decomposition of older, recalcitrant soil C pools in this ecosystem is relatively unimportant 13 years after a stand replacing fire. Our results also indicate that realistic predictions and modeling of terrestrial C cycling must account for the variability in tree density and stand age that exists across the landscape as a result of natural disturbances.     

Characterization of polymorphic microsatellite loci for the polychaete tubeworm Hobsonia florida

Eight dinucleotide microsatellite loci were isolated and characterized from Hobsonia florida, a tube‐dwelling ampharetid polychaete. The identified loci were highly polymorphic, with allelic diversity ranging from six to 11 alleles. Levels of expected heterozygosity were 0.52 or greater in all cases, averaging 0.78 across the complete set of loci. Cross‐species amplification was successful in three of the eight loci for one or both of the other species (Melinna cristata and Ampharete acutifrons) tested. Although these novel loci were designed for immediate utility in H. florida population‐level research, these results indicate they may prove useful in studies of other related taxa.     

Unsuspected cryptic polymorphism in the polychromatic Midas cichlid.

The Midas cichlid ( Cichlasoma citrinellum ) of Nicaragua shows stable polychromatism in that a consistent, small proportion of the fish in nature lose their melanophores and thereby become gold-coloured. Before metamorphosis, all fish look alike. We asked whether the pre-transformed offspring of gold and normal morphs might differ in their morphological and physiological responses to white and to black backgrounds despite looking the same. More chromatophores developed in all juveniles exposed for two weeks to a black than to a white background. When moved from one background to the other, the fish adjusted to white faster than to black. Most importantly, genetically normal fish (N) colour-matched quicker than genetically gold fish (G) irrespective of the direction of change. Adjustment in G was also more variable, indicating poorer control. A parallel pattern was recorded photometrically in melanophores of excised scales: aggregation of pigment was faster than dispersion. And pigment in the melanophores of N aggregated and dispersed swifter than did those of G. Therefore, pre-metamorphosed juvenile G could be more vulnerable to predation than are juvenile N. This reveals a possible source of selection against the offspring of gold morphs before they become gold-coloured.     

Brachiopod orientation to water movement: functional morphology

Previous work by the author has shown that Laqueus californianus. Terebratulina unguicula , and. to a lesser extent, Hemithyris psittacea will actively reorient to water currents in the laboratory; Terebratalia transversa will not. This active reorientation is effected primarily by the dorsal adjustor muscles; the ventral adjustors function to depress and tilt the shell. The torque around the pedicle generated by drag on the shell is low at moderate current speeds. The dorsal adjustor muscles are competent to resist these torques up to current speeds of 35 cm/s for L. californianus and H. psittacea and 56 cm/s for T. unguicula . Shell shape, gross pedicle form, and form of the pedicle foramen are unreliable indicators of a brachiopod's ability to actively reorient. Shape of the pedicle bulb and position and size of the pedicle connectives are better indicators but. on functional grounds, the dorsal adjustor muscle morphology is the best indicator of active reorientation. An angle α (the maximum possible rotation of the shell that can be produced by contraction of one of the dorsal adjustor muscles) correlates well with both the maximum observed rotations and the exhibition of active reorientation to currents. For fossil material, the existence of dorsal adjustor muscle scars that touch medially should also be a good indicator of active reorientation ability.     

Nitrate Uptake by Manganese-Deficient Lemon Plants

The uptake of nitrate and water was followed in Eureka lemon (Citrus limon (L.) Burm. f.) plants grown in solution culture in a greenhouse under short (3–6 months) and long-term (22–24 months) Mn-nutrition stress. Uptake was determined from depletion in the nutrient solution. Under short-term stress, manganese-deficient plants absorbed 14.5% more nitrate and 3.4% more water than the control plants, on a weight basis. Under long-term stress there was a three-fold increase in nitrate and a two-fold increase in water uptake in the Mn-deficient plants. The intensive nitrate uptake under Mn-deficiency stress was more spectacularly demonstrated in plants which were exposed also to low nitrogen supply. The low-nitrogen Mn-deficient plants absorbed more nitrate, had less stunted growth and developed fewer visible symptoms of both N and Mn deficiencies than high-nitrogen Mn-deficient plants.     

The biology of some Argiope species from New Guinea: predatory behaviour and stabilimentum construction (Araneae: Araneidae)

Three species of Argiope: A. picta, A. aemula and A. reinwardti were studied at Wau, New Guinea. The stabilimenta in 548 webs of these species were classified into 18 categories, and the frequency of occurrence of each category was recorded. The data from this study are compared with previous records on the variation in the form of the devices built by spiders of the genera Argiope and Gasteracantha and related to theories about stabilimentum function.
Studies of the predatory behaviour of the three species show that this is, in general, similar to that of Argiope argentata . Data are cited to show that the spiders discriminate lepidopterans from insects of similar size. Particular attention was paid to the question of whether the species interrupt predatory sequences, after the attack phase, with a stage during which they rest at the hub of the web before transporting the prey. Unlike Argiope argentata these species interrupt a high proportion of predatory sequences that are initiated by bite/wrap attacks. This aspect of their behaviour is evaluated and discussed.