Nests

SUMMARYMechanisms affecting patterns of vector distribution among host individuals may influence the population and evolutionary dynamics of vectors, hosts and the parasites transmitted. We studied the role of different factors affecting the species composition and abundance of Culicoides found in nests of the blue tit (Cyanistes caeruleus). We identified 1531 females and 2 males of 7 different Culicoides species in nests, with C. simulator being the most abundant species, followed by C. kibunensis, C. festivipennis, C. segnis, C. truncorum, C. pictipennis and C. circumscriptus. We conducted a medication×fumigation experiment randomly assigning bird's nests to different treatments, thereby generating groups of medicated and control pairs breeding in fumigated and control nests. Medicated pairs were injected with the anti-malarial drug Primaquine diluted in saline solution while control pairs were injected with saline solution. The fumigation treatment was carried out using insec...

Abstract 1. Colony organisation and movement behaviour of the Argentine ant (Linepithema humile) was studied over 3 years in field populations in California and in captive colonies in the laboratory. This invasive species is highly polydomous and unicolonial; colonies consist of expansive and fluid networks of nests and trails. The spatial and temporal organisation of colonies may contribute to ecological dominance.2. Argentine ant nests and inter-nest trails shift in size, abundance, and location, so that colony networks are spatially contracted in the winter and expanded spring to autumn. Colonies occupy permanent sites; ants migrated to and from the same winter nest locations year after year, and occupied 30% of the same nests repeatedly during seasonal migrations.3. Nests were moved on average 2–3 m. Forty-two per cent were occupied less than 1 month, 4% the entire study, and the other 54% lasted 3.9 ± 2.3 months (mean ± SD).4. Nests were located within 2–4 m of woody plants, in warm sites in the winter and cool sites in the summer. Both humidity and food availability influenced nest-site choice in laboratory colonies. However, when faced with a trade-off between factors, the ants chose humid nest boxes over nest boxes near food, and ants moved nests only in response to changes in humidity and not distance to food.5. The results indicate that L. humile colonies are seasonally polydomous, and that nest movements are driven by changes in microclimate. Colony organisation maintains high local density and increases food supply, which may improve the competitive ability of L. humile colonies and reduce opportunities for species coexistence.

Social insects use a complex of recognition cues when discriminating nestmates from non-nestmate conspecifics. In the Argentine ant, Linepithema humile, recognition cues can be derived from exogenous sources, and L. humile acquires prey-derived hydrocarbons that are used in nestmate discrimination. We studied Argentine ant population-level distinctions in response to external recognition cues. Ants belonging to a California population were strongly affected by the imposition of prey-derived hydrocarbons, with spatially isolated colony fragments that had been fed different cockroach prey (Blattella germanica or Supella longipalpa) showing high and injurious intracolony aggression when reunited. In contrast, colonies of Argentine ants from the southeastern U.S. showed only moderate and noninjurious aggression when subjected to the same treatment. Field-collected colonies of L. humile had hydrocarbons in the range of those provided by S. longipalpa, and colonies from the southeastern U.S. had significantly higher initial levels of Supella-shared hydrocarbons. When fed cockroaches, Argentine ants from both regions acquired additional amounts of Supella- and Blattella-specific hydrocarbons, with a significant increase in levels of Blattella-specific hydrocarbons. Therefore, diet partitioning produced a greater change in the proportion of prey hydrocarbons in the California than in the southeastern U.S. populations, which may be responsible for the altered behaviour observed in the California population. Identifying factors underlying geographical variation in cue expression and/or perception may bring us closer to elucidating the selective forces driving nestmate recognition systems.

La descomposición es un proceso fundamental de los ecosistemas. En ambientes áridos y semiáridos, estos procesos se ralentizan debido a las condiciones climáticas desfavorables para la actividad microbiana, por lo que, organismos como las hormigas se vuelven claves ya que en sus nidos acumulan materia orgánica como consecuencia de su actividad de forrajeo. Nuestro objetivo fue evaluar la influencia de los nidos de Acromyrmex lobicornis sobre el proceso de descomposición del material circundante. Se enterraron 42 bolsas de hojarasca en 7 arbustos con y sin hormiguero (tres bolsas por arbusto). A los 21, 35 y 60 días, las bolsas fueron retiradas, limpiadas, pesadas, secadas y calcinadas. La tasa de descomposición en nidos de A. lobicornis fue significativamente menor con respecto a la de suelos sin hormigueros. La marcada estacionalidad en el desierto del monte y la esterilización del nido podrían ser algunos de los causantes.

The loggerhead sea turtle (Caretta caretta) nests on sand beaches, has both oceanic and neritic life stages, and migrates internationally. We analyzed an 18-year time series of Index Nesting Beach Survey (Index) nest-count data to describe spatial and temporal trends in ...

SUMMARYMechanisms affecting patterns of vector distribution among host individuals may influence the population and evolutionary dynamics of vectors, hosts and the parasites transmitted. We studied the role of different factors affecting the species composition and abundance of Culicoides found in nests of the blue tit (Cyanistes caeruleus). We identified 1531 females and 2 males of 7 different Culicoides species in nests, with C. simulator being the most abundant species, followed by C. kibunensis, C. festivipennis, C. segnis, C. truncorum, C. pictipennis and C. circumscriptus. We conducted a medication×fumigation experiment randomly assigning bird's nests to different treatments, thereby generating groups of medicated and control pairs breeding in fumigated and control nests. Medicated pairs were injected with the anti-malarial drug Primaquine diluted in saline solution while control pairs were injected with saline solution. The fumigation treatment was carried out using insec...

Although the primary goal of English language instruction is to assist students in acquiring communicative competence in l, developing this ability might be very challenging for teachers since not all language learners of English are willing to communicate in the target language. In order to develop their learners' communication skills and increase their students' willingness to speak, teachers utilize different techniques. The aim of this qualitative study is to find out and compare the speaking techniques that are used by native (NESTs) and non-native (NNESTs) instructors of English Preparatory Programs at universities around Turkey. Data gathered from the open-ended questionnaire revealed both similarities and differences among NESTs and NNESTs about implementing various techniques in EFL speaking classes. The findings of the study suggested some pedagogical implications both for instructors and students in relation to the improvement of the students' oral performance in language preparatory programs.