Isabel Alves-dos-Santos

Biodiversity, Species Interactions and Ecological Networks in a Fragmented World

Biodiversity is organised into complex ecological networks of interacting species in local ecosystems, but our knowledge about the effects of habitat fragmentation on such systems remains limited. We consider the effects of this key driver of both local and global change on both mutualistic and antagonistic systems at different levels of biological organisation and spatiotemporal scales. There is a complex interplay of patterns and processes related to the variation and influence of spatial, temporal and biotic drivers in ecological networks. Species traits (e.g. body size, dispersal ability) play an important role in determining how networks respond to fragment size and isolation, edge shape and permeability, and the quality of the surrounding landscape matrix. Furthermore, the perception of spatial scale (e.g. environmental grain) and temporal effects (time lags, extinction debts) can differ markedly among species, network modules and trophic levels, highlighting the need to develop a more integrated perspective that considers not just nodes, but the structural role and strength of species interactions (e.g. as hubs, spatial couplers and determinants of connectance, nestedness and modularity) in response to habitat fragmentation. Many challenges remain for improving our understanding: the likely importance of specialisation, functional redundancy and trait matching has been largely overlooked. The potentially critical effects of apex consumers, abundant species and super-generalists on network changes and evolutionary dynamics also need to be addressed in future research. Ultimately, spatial and ecological networks need to be combined to explore the effects of dispersal, colonisation, extinction and habitat fragmentation on network structure and coevolutionary dynamics. Finally, we need to embed network approaches more explicitly within applied ecology in general, because they offer great potential for improving on the current species-based or habitat-centric approaches to our management and conservation of biodiversity in the face of environmental change.

Nesting Biologies and Immature Stages of the Tapinotaspidine Bee Genera Monoeca and Lanthanomelissa and of Their Osirine Cleptoparasites Protosiris and Parepeolus (Hymenoptera: Apidae: Apinae)

Abstract The nesting biologies of Monoeca haemorrhoidalis (Smith) and Lanthanomelissa betinae Urban (Tapinotaspidini) are described from southeastern Brazil. Both are ground nesting; the nests of the former are attacked by the cleptoparasite Protosiris gigas Melo (Osirini), and those of the latter are attacked by Parepeolus minutus Roig-Alsina (Osirini). Egg eclosion, larval feeding behavior, and cocoon spinning of M. haemorrhoidalis are detailed. A female of P. gigas opens the closed cell of M. haemorrhoidalis by making a large opening in the cell cap (which is plugged after ovipositioning) through which she apparently extends her metasoma. Indirect evidence suggests that she uses her metasomal apex, and perhaps even the sting, to kill the host egg or early instar. Protosiris eggs are either attached to the cell-wall surface of the nearly vertical host cells or dropped onto the surface of the provisions. First instars of P. gigas, with strongly curved, sharply pointed mandibles, are also capable of killing host immatures or competing cleptoparasites. Cocoons of all four species are compared and contrasted. The egg, all larval instars, and pupa of Monoeca haemorrhoidalis are described, as are the egg and postdefecating larva of Lanthanomelissa betinae. The egg, all larval instars, and pupa of Protosiris gigas are described, as is the postdefecating larva of Parepeolus minutus. Both Monoeca haemorrhoidalis and Protosiris gigas have four ovarioles per ovary. The egg indices and other ovarian features of both species are identified and discussed. The possible phylogenetic relationship of the Tapinotaspidini with the Osirini is briefly explored on the basis of data from this study. Possible phylogenetic relationships of the Osirini with other cleptoparasitic apids are analyzed. In the appendix,, the identity of the species of Monoeca, whose nesting biology is presented in the main paper, is discussed. The species is M. haemorrhoidalis (Smith, 1854), a species closely related to M. schrottkyi (Friese, 1902) and M. xanthopyga Harter-Marques, Cunha, and Moure, 2001. An identification key for distinguishing these three species is presented. Tetrapedia piliventris Friese is placed as a junior synonym of M. haemorrhoidalis (new synonymy). A lectotype is designated for Pachycentris schrottkyi Friese. The species of Protosiris found attacking M. haemorrhoidalis is here described as new, P. gigas Melo sp. nov. It is structurally most similar to P. caligneus (Shanks), from which it differs by its abundant yellow marks, plumose pubescence on the lower paraocular area, protruding anterior mesoscutum, and sparser punctation on the metasomal terga. Appendix: Taxonomic Notes on Monoeca and Description of a New Species of Protosiris, by Gabriel A. R. Melo

O uso de diferentes métodos para amostragem da fauna de abelhas (Hymenoptera: Apoidea), um estudo em floresta ombrófila mista em Santa Catarina

A survey of the bee fauna of Araucaria Forest was performed in the border of a fragment in the district of Porto União, in Santa Catarina State. Samples were carried on monthly between October/2005 and October/2006 with hand nets directly on the flowers, besides three types of traps: chemical baits, trap nests and pantraps. A total of 1711 bees were captured belonging to 164 species, distributed in five families of bees that occur in Brazil. From the total 1339 bees of 130 species were sampled with the hand net, 346 individuals of 72 species were collected in pantraps, 24 bees of nine species were caught in the trap nests and two specimens of one species were sampled with baits. At most 48 species were common to two or more sample methods. Dialictus, with 27 species, was the most representative genus in the area. The exotic Apis mellifera L. was the most abundant species, representing 49.6% of the sampled bees, following by Dialictus sp.11 with 3.2%. The results show evidences of a seasonal pattern of activity of the bees and the importance of the use of complementary methods to survey the fauna. The composition of the bee fauna was similar to many inventories performed in the Araucaria Forest, being Halictidae the most diverse family followed by Apidae.

Bees, birds and yellow flowers: pollinator-dependent convergent evolution of UV patterns

Colour is one of the most obvious advertisements of flowers, and occurs in a huge diversity among the angiosperms. Flower colour is responsible for attraction from a distance, whereas contrasting colour patterns within flowers aid orientation of flower visitors after approaching the flowers. Due to the striking differences in colour vision systems and neural processing across animal taxa, flower colours evoke specific behavioural responses by different flower visitors. We tested whether and how yellow flowers differ in their spectral reflectance depending on the main pollinator. We focused on bees and birds and examined whether the presence or absence of the widespread UV reflectance pattern of yellow flowers predicts the main pollinator. Most bee-pollinated flowers displayed a pattern with UV-absorbing centres and UV-reflecting peripheries, whereas the majority of bird-pollinated flowers are entirely UV- absorbing. In choice experiments we found that bees did not show consistent preferences for any colour or pattern types. However, all tested bee species made their first antennal contact preferably at the UV-absorbing area of the artificial flower, irrespective of its spatial position within the flower. The appearance of UV patterns within flowers is the main difference in spectral reflectance between yellow bee- and bird-pollinated flowers, and affects the foraging behaviour of flower visitors. The results support the hypothesis that flower colours and the visual capabilities of their efficient pollinators are adapted to each other.

Desafios atuais da modelagem preditiva de distribuição de espécies

Predictive modelling has been used to analyze species geographic distribution through extrapolation of environmental characteristics of known occurrence areas. Interest in this kind of modelling is derived from the need for rapid and well-grounded answers to the threats faced by species due to habitat loss, exotic species invasion, climate changes, and others. This article provides an overall view of recent advances in modelling and aims to encourage the discussion and application of this method that can help with basic biological knowledge acquisition as well as with public policies aimed at their conservation.

Aspectos morfológicos e comportamentais dos machos de Ancyloscelis Latreille (Anthophoridae, Apoidea)

Specimens of five bee species of the genus Ancyloscelis Latreile, 1836 were sampled during three consecutive years in Rio Grande do Sul, Brazil, with the aim to study their morphology and behavior during flower visits. Characteristics that allow to distinguish the five species are presented.

Phoretic mites (Acari: Chaetodactylidae) associated with the solitary bee Tetrapedia diversipes (Apidae: Tetrapediini)

Solitary bees of the genus Tetrapedia have a specific association with mites of the genus Roubikia (Chaetodactylidae). These mites are frequently found attached to active Tetrapedia bees. We quantified the number of mites on individuals of Tetrapedia diversipes Klug and examined the interaction between these species. Nests of T. diversipes were obtained from trap-nests placed in four localities in São Paulo, Brazil. The study lasted from March 2007 to February 2009. Out of a total of 650 nests with emergences, 118 were infested with mites (Roubikia sp.). From these nests, 176 individuals of T. diversipes emerged with mites on their bodies. Additionally, six individuals of Coelioxoides waltheriae, the specific kleptoparasitic bee to T. diversipes, emerged. Mites were attached mainly to the mesosoma. All nests infected with mites did not presented mortality of the immature. The mortality rate of nests was inversely related to the level of mite infestation, suggesting a mutualistic interaction in which mites may remove fungi from the nests, while the bees would provide the mites with transport, dispersal, and shelter.

Quando um visitante floral é um polinizador

Os visitantes florais sao animais que buscam, nas flores, recursos para si ou para sua prole. As vezes uma mesma planta pode receber um espectro grande de visitantes, como e o caso de especies cujas flores oferecem muito nectar. Porem, nem todo visitante floral realiza a polinizacao. Para ser um polinizador efetivo e necessario cumprir alguns requisitos, como: contato com a antera e o estigma, frequencia de visita suficiente, fidelidade floral e a realizacao de uma rota adequada de visitacao. Em muitos trabalhos sobre a estrutura de comunidades e, principalmente, sobre a rede trofica (ex. animal-planta), os autores adotam o termo polinizador para todo e qualquer visitante floral, categorizando-os com o mesmo papel e funcao para a planta. Neste trabalho, relatamos casos de visitantes florais que sao polinizadores legitimos e efetivos, dos quais a planta depende de seu servico para producao de frutos e sementes, distinguindo-os daqueles visitantes que nao efetuam a polinizacao, ou nao se tem certeza que o facam. Assim, espera-se ilustrar as diferencas, dando a devida importância e o peso correto para os muitos visitantes. Utilizamos abelhas como modelo, mas a ideia pode ser extrapolada para qualquer outro grupo de polinizador.

Floral-oil-producing Plantaginaceae species: geographical distribution, pollinator rewards and interactions with oil-collecting bees

Floral oils as reward to pollinators occur in eleven plant families and appeared at least 28 times in the evolutionary history of flowering plants. They are produced in epithelial or tricomatic glands and collected by oil bee visitors. The present paper focuses on floral-oil-producing species of Plantaginaceae, a Neotropical group namely Angelonia clade. This group comprises around 40 described species in the genera Angelonia, Basistemon, Monttea, Monopera and the oil-less Melosperma. We present a revision of all species of the Angelonia clade, their geographical distribution, resources offered to pollinators and records of flower visitors, especially oil-collecting bees. These plants rely only on oil-collecting species in the tribe Centridini and Tapinotaspidini for a successful pollination, being the interaction between both partners an especial case of bee/flower adaptation in Neotropical region. Some bee species depend only on the oil of Plantaginaceae flowers to survive, while others can collect on several floral oil sources. The pollinating bees explore the oil glands located in sacs using specialized hairs in the forelegs. With this study, we hope to inspire further research relating to this fascinating group of plants, in which most species are rare and occur in highly endangered habitats in South American open vegetation biomes.

As abelhas do gênero Xylocopa Latreille (Xylocopini, Apidae) do Estado de São Paulo, Brasil

This study contributes to the knowledge about the diversity of bees belonging to the genus Xylocopa Latreille, 1802 of the Sao Paulo State through a compilation of taxonomic and biological information. Identification keys are presented for the four subgenera (DasyxylocopaHurd & Moure, 1963; NeoxylocopaMichener, 1954; Schonnherria Lepeletier, 1841 and StenoxylocopaHurd & Moure, 1960) and for the 22 species recorded for the state, beyond the available data on its biology, plants visited and geographic occurrence.