Phoretic association between Hisonotus chromodontus (Loricariidae: Hypoptopomatinae) and Ichthyocladius sp. (Diptera: Chironomidae) larvae in Amazonian streams / Associação forética entre Hisonotus chromodontus (Loricariidae: Hypoptopomatinae) e larvas de Ichthyocladius sp. (Diptera: Chironomidae) em riachos amazônicos

Abstract: Larvae of non-biting midges in the family Chironomidae can be found in association with several species of fish in the family Loricariidae. In this study, we describe the first record of phoretic interaction between larvae of Ichthyocladius sp. and the fish Hisonotus chromodontus in streams in the Amazon basin. Between July 2010 and March 2019, fish were collected from three streams of the Teles Pires River basin in the state of Mato Grosso, Brazil. We investigated the attachment site of chironomid larvae on the body of fish and the frequency of attachment. A total of 1.241 specimens of H. chromodontus were collected, among which nine hosts were found carrying in the ventral region a single Ichthyocladius sp. specimen. All Ichthyocladius sp. were attached to a spicule of fish between the pectoral and pelvic fins, in which they were observed at the fourth developmental stage at the beginning of the cocoon construction (1.50 mm). In addition, a pre-pupa larva (2.60 mm) and an empty cocoon (2.50 mm) were reported. The Loanda stream had the highest occurrence of this type of association (of 12 fish examined, three had larvae). The other two streams reported a lower occurrence: the Baixada Morena stream had three fish associated with larvae amongst 1105 fish examined, whereas the Selma stream had three out of 124 fish infested by larvae. The occurrence of only one larva per host can be related to the small body area of the host fish (average standard length = 26.60 mm and average weight = 0.31 g). We observed that the larvae prefer fixation sites in the vicinity of the pectoral and pelvic fin of the fish, which is presumably associated with the fact that chironomids feed on algae and debris suspended by the movement of loricariids. These streams differ with respect to the presence of riparian forests, which may affect resource availability and thereby influence ecological interactions between the species.

Resumo: Larvas de mosquitos da família Chironomidae podem ser encontradas em associação com várias espécies de peixes da família Loricariidae. Neste estudo, descrevemos o primeiro registro de interação forética entre larvas de Ichthyocladius sp. e o Hisonotus chromodontus em riachos da bacia amazônica. Entre julho de 2010 e março de 2019, foram coletados peixes em três riachos da bacia do rio Teles Pires, no estado de Mato Grosso, Brasil. Nós investigamos o local de fixação das larvas de quironomídeos no corpo dos peixes e a frequência da fixação. Um total de 1.241 espécimes de H. chromodontus foram coletados, entre os quais nove hospedeiros foram encontrados carregando, na região ventral, um único espécime de Ichthyocladius sp. Todos os Ichthyocladius estavam aderidos a uma espícula do peixe entre as nadadeiras peitoral e pélvica, onde foram observados no quarto estágio de desenvolvimento, no início da construção do casulo (1,50 mm), além de uma pré-pupa (2,60 mm) e um casulo vazio (2,50 mm). O riacho Loanda apresentou a maior ocorrência de hospedeiros na associação (de 12 peixes examinados, três estavam com larvas) e o menor registro foi para o riacho Selma (dos 1105 peixes examinados, três estavam infestados). A ocorrência de apenas uma larva por hospedeiro pode estar relacionada à pequena área corporal do peixe hospedeiro (comprimento padrão médio = 26,60 mm e peso médio = 0,31 g). Observamos que as larvas preferem locais de fixação nas proximidades da nadadeira peitoral e pélvica dos peixes, o que está presumivelmente associado ao fato dos quironomídeos se alimentarem de algas e detritos suspensos pelo movimento dos loricarídeos. Os riachos diferem com relação à presença de matas ciliares, que podem afetar a disponibilidade de recursos e, assim, influenciar as interações ecológicas entre as espécies.

Research progress in effects of interspecific interaction on medicinal plants in intercropping system / 中国中药杂志

Intercropping farming system is one of the essence of traditional agriculture in China and one of the most common and basic patterns of modern ecological planting. Intercropping system uses the principle of species diversity to create reasonable interspecific interaction conditions with obvious productivity advantages. In this paper, the interspecies interaction is divided into aboveground and underground parts from the space view, and its influence and mechanism on the yield and secondary metabolites of medicinal plants are elaborated.The interspecific interaction in the aboveground part mainly introduces the distribution and utilization of space resources among plants. The interspecific interaction in the underground part mainly introduces the soil rhizosphere effect and related mediating factors, root exudates, soil microorganisms, root space structure and soil environmental factors. On the basis of understanding the mechanism of interspecific interaction, this paper further discusses the application of intercropping in traditional Chinese medicine ecological agriculture, taking the effective control of diseases and insect pests, the increase of medicinal material yield and the improvement of medicinal material quality as the benefit index, so as to seek better advantages of intercropping and provide ideas for the utilization of intercropping production mode in traditional Chinese medicine ecological agriculture.

How do guiana dolphin (sotalia guianensis), from the cananéia estuary in state of São Paulo, use cerco-fixo fish traps in their fishing activities?

In the Cananéia estuary there is a rare positive interaction between a cetacean and a type of fishing activity. In this region the Guiana dolphin (Sotalia guianensis) uses cerco-fixo fish traps to corner shoals and reduce the escape routes of their prey, and in doing this increase their capture efficiency. The object of this study was to evaluate, by means of a quantitative analysis, how the Guiana dolphin uses the cerco-fixo fish trap in their fishing activities. Their behaviors were quantified separately according to a group structure, so as to also verify how their behaviors vary according to the number of individuals involved in the strategy. This approach serves to improve understanding about what the role of the trap in fishing strategies is and how its use, such as using it as a shield to block the shoals, influences the frequency of behaviors executed during fishing activities.

Habitat simplification affects nuclear-follower foraging association among stream fishes

A interação nuclear-seguidor é um tipo particular de associação alimentar interespecífica que envolve uma espécie nuclear, que revolve ou vasculha o substrato, e espécies seguidoras, que acessam os itens alimentares disponibilizados pela atividade do nuclear. Neste estudo investigamos o efeito da estrutura do habitat sobre essa interação em um riacho no Planalto da Bodoquena, Centro-Oeste do Brasil. Foram registradas 272 interações durante 24 sessões de observação subaquática em áreas estruturalmente inalteradas e alteradas. A espécie nuclear dominante diferiu entre as áreas. Prochilodus lineatus foi a espécie nuclear dominante das áreas alteradas, enquanto que Leporinus macrocephalus foi a espécie nuclear dominante nas áreas inalteradas. A riqueza de espécies seguidoras por interação não diferiu entre as áreas, entretanto a abundância de seguidores foi maior nas áreas inalteradas do que nas alteradas. Essas diferenças parecem ser consequência das modificações na composição da comunidade e no comportamento alimentar das espécies nucleares que são, por sua vez, decorrentes das diferenças na composição do substrato e disponibilidade de alimento entre as áreas estruturalmente distintas.

Nuclear-follower interaction is a particular kind of interspecific foraging association that includes a nuclear species, which dig in or inspect the bottom, and follower species, which access the food items made available by the nuclear. In this study we examined the effect of habitat structure on nuclear-follower relationship in a stream of Bodoquena Plateau, Central-West Brazil. Foraging associations were registered while snorkeling in 24 observation sessions, totaling six hours in unaltered and altered sites. Overall, 272 nuclear-follower associations were registered, having four species acting as nuclear and seven as followers. The dominant nuclear species were different in each site. Prochilodus lineatus was the main nuclear species in the altered site and Leporinus macrocephalus in the unaltered site. The richness of follower species was similar between sites, however, follower species abundance per interaction were significantly higher in the unaltered site than in the altered site. These differences seem to be a consequence of the alterations in assemblage composition and feeding behavior of the nuclear species that presumably are affected by different substrate composition and food availability between the structurally distinct areas.

Cleptoparasite eees, with emphasis on the oilbees hotts / Abejas cleptoparásitas, con énfasis en las abejas hospederas coletoras de aceite

Cleptoparasite bees lay their eggs inside nests constructed by other bee species and the larvae feed on pollen provided by the host, in this case, solitary bees. The cleptoparasite (adult and larvae) show many morphological and behavior adaptations to this life style. In this paper I present some data on the cleptoparasite bees whose hosts are bees specialized to collect floral oil.

Las abejas Cleptoparásitas depositan sus huevos en nidos construídos por otras especies de abejas y las larvas se alimentan del polen que proveen las hospederas, en este caso, abejas solitarias. El cleptoparásito (adulo y larva) muestra muchas adaptaciones morfológicas y comportamentales para este estilo de vida. En este manuscrito presento datos sobre abejas cleptoparásitas cuyos hospederos son abejas especializadas en recolectar aceite floral.

Feeding association between benthic and nektonic Neotropical stream fishes

Following behaviour among Neotropical stream fishes have been scarcely reported. This type of feeding association was observed in a small stream in the upper rio Paraná system between the catfish, Aspidoras fuscoguttatus, acting as a nuclear species, and Knodus moenkhausii, Poecilia reticulata, and Astyanax altiparanae as follower species. Aspidoras fuscoguttatus individuals dug in the bottom during feeding, causing sediment suspension. Their followers picked food items in the "cloud" of suspended particles. Food items of sediment are no longer consumed by the catfish when in suspension, but are still available for K. moenkhausii, P. reticulata and A. altiparanae. Following behaviour is an alternative feeding tactic for these species, which reinforces the general idea of behavioural plasticity among follower species.

A interação nuclear-seguidor tem sido raramente registrada entre peixes de riachos Neotropicais. Este tipo de associação foi observada em um riacho de cabeceira, no sistema do Alto rio Paraná envolvendo o cascudinho, Aspidoras fuscoguttatus, como espécie nuclear, e Knodus moenkhausii, Poecilia reticulata e Astyanax altiparanae como seus seguidores. Indivíduos de Aspidoras fuscoguttatus revolveram o substrato durante alimentação, promovendo a suspensão de sedimento. Os seguidores, por sua vez, movimentaram-se pela "nuvem" de partículas em suspensão, capturando itens alimentares. As particulas alimentares em suspensão parecem não ser utilizadas pelo cascudinho, mas tornam-se disponíveis para K. moenkhausii, P. reticulata e A. altiparanae. O comportamento de seguidor representa uma tática alimentar alternativa para estas espécies, reforçando a idéia geral de plasticidade comportamental entre as espécies seguidoras.