Consequences of floral visits by ants and invasive honeybees to the hummingbird‐pollinated,Caribbean cactus Melocactus intortus

The pink, tubular, nectariferous flowers of Melocactus intortus (Cactaceae) in Puerto Rico are visited by native hummingbirds (Anthracothorax dominicus), but also by invasive honeybees (Apis mellifera) and ants (Solenopsis sp.). We sought to determine if the bees and ants significantly alter the pollination of M. intortus by measuring pollinator effectiveness. Using traditional estimates of effectiveness (visitation rate and seed set), our results show that hummingbirds were the most effective pollinators as expected. Bees and ants were less effective, and their contributions were one‐fourth to one‐tenth of that observed for hummingbirds. We then modified this measure of effectiveness by adding two components, fitness of progeny and temporal availability of visitors, both of which refine estimates of flower visitor effectiveness. With these new estimations, we found that the effectiveness values of all three animal visitors decreased; however, the role of hummingbirds as the principal pollinator was maintained, whereas the effectiveness values of bees and ants approached zero. By these new measures of overall pollinator effectiveness, the invasive honeybees and ants have little effect on the reproductive success of M. intortus.     

Mind Architecture and Brain Architecture

The use of the computer metaphor has led to the proposal of mind architecture (Pylyshyn 1984; Newell 1990) as a model of the organization of the mind. The dualist computational model, however, has, since the earliest days of psychological functionalism, required that the concepts mind architecture and brain architecture be remote from each other. The development of both connectionism and neurocomputational science, has sought to dispense with this dualism and provide general models of consciousness – a uniform cognitive architecture –, which is in general reductionist, but which retains the computer metaphor. This paper examines, in the first place, the concepts of mind architecture and brain architecture, in order to evaluate the syntheses which have recently been offered. It then moves on to show how modifications which have been made to classical functionalist mind architectures, with the aim of making them compatible with brain architectures, are unable to resolve some of the most serious problems of functionalism. Some suggestions are given as to why it is not possible to relate mind structures and brain structures by using neurocomputational approaches, and finally the question is raised of the validity of reductionism in a theory which sets out to unite mind and brain architectures.     

Sperm package morphology in scorpions and its relation to phylogeny

Sperm packages are widespread in the order Scorpiones, but absent in the family Buthidae. The morphology of sperm packages is diverse and apparently has phylogenetic information. The objectives of this work were to show diversity of sperm packages and to provide a quantitative basis for using sperm packages’ morphology as a taxonomic character. For this, we conducted a morphological analysis and comparison of the different sperm packages of species of the family Bothriuridae. The seminal content from males of species of Bothriuridae was studied. Specimens from Iuridae, Buthidae, Euscorpiidae, Liochelidae, Scorpionidae, Vaejovidae, Chaerilidae, and Chactidae were used for comparison. Digital images of sperm packages were measured and statistically analysed based on the following variables: total length, head width, head–body angle, total area, and head length. Pairs of variables were also contrasted, and all the variables were correlated with the current phylogenetic hypothesis for Bothriuridae. High morphological diversity and variability in measures was observed. In general, measurements were similar within each genus, but differed amongst genera. Cane‐like sperm packages are very common in species of the family Bothriuridae. Species from Bothriurus show a wide range of sperm package shapes, some of them shared with Timogenes and Vachonia species, supporting the idea of nonmonophyly of the genus. Many species showed sperm package dimorphism inside a single male. Some of the analysed features fit well with the phylogenetic hypothesis in Bothriuridae, and the general package shape shows high correlation with scorpion phylogeny in other families. Bent and round packages are the most common amongst the different families. Sperm packages are not developed in Chaerilidae, as in Buthidae. This is the first morphological and comparative analysis of sperm packages in scorpions, and reveals much greater diversity in this trait than previously known. Our results reinforce the idea that the study of morphology of sperm packages would contribute characters for scorpion phylogeny at different levels. © 2011 The Linnean Society of London, Zoological Journal of the Linnean Society, 2011, 161 , 463–483.     

Predation by the tropical plant Utricularia foliosa

1. We examined the prey captured by individual plants of the tropical carnivorous plant Utricularia foliosa, located in different areas along a creek in the Colombian Amazon and the zooplankton and macroinvertebrate communities associated with the plants. The aims were: (i) to determine whether bladders of different sizes within each plant catch different numbers of prey or exploit different size ranges and types of prey, (ii) if the quantity and composition of prey captured varies temporally and/or spatially and (iii) if the plant has evolved effective mechanisms of attracting prey. 2. Utricularia foliosa captured the most abundant species of macroinvertebrates associated with the plant. Larger bladders captured more, larger and more diverse prey. However, benefits of the extra prey caught by large bladders were not offset by the greater cost of producing bladders larger than approximately 1650 μm. 3. The number of prey captured was higher in those plants with more carbohydrates per bladder and with a higher ratio of antenna size/bladder length. The antennae enhance capture success by offering the prey a favourable substratum that exploits their natural locomotor and feeding behaviour. However, although carbohydrates may lure prey, carbohydrate production was not a strategy of the plant to enhance the capture of prey, because the amount of carbohydrates in the bladder was related to the abundance of periphyton.