Due to features that make them outstanding environmental bioindicator, colonies of Apis mellifera are being used to study environmental pollution. The primary objective of this research was to use honeybee colonies to identify heavy metals and determine their utility for environmental management. Five stations each with two A. mellifera hives were strategically located in urban, industrial, agricultural and forested areas within the municipality of Córdoba (Spain), and foraging bees were collected from April to December in 2007, 2009 and 2010 to analyse spatial and temporal variation in Pb, Cr, Ni and Cd pollution. Metal concentrations, in milligram per kilogram of honeybee, were determined by inductively coupled plasma-atomic emission spectrometry and graphite furnace atomic absorption spectrophotometry. Significant differences in concentrations were found among the various locations and periods. The highest number of values exceeding the upper reference thresholds proposed for this study (Pb, 0.7 mg/kg; Cr, 0.12 mg/kg; Ni, 0.3 mg/kg; and Cd, 0.1 mg/kg) was observed for Pb and Cr (6.25% respectively), station S4 (13.22%), year 2007 (20.83%) and in months of May and July (11.90% each). Regarding the Cd, which was analysed only in 2010, the highest number of values exceeding the upper reference thresholds was 40%. Biomonitoring with colonies of A. mellifera could contribute to improved surveillance and control systems for atmospheric pollution by integrating qualitative and quantitative assessments, thus facilitating prevention and readiness in the event of environmental crises.

Background Host range is a fundamental trait to understand the ecological and evolutionary dynamics of symbionts. Increasing host specificity is expected to be accompanied with specialization in different symbiont traits. We tested this specificity-specialization association in a large group of 16 ant-associated silverfish species by linking their level of host specificity to their degree of behavioural integration into the colony and to their accuracy of chemically imitating the host’s recognition system, i.e. the cuticular hydrocarbon (CHC) profile. Results As expected, facultative associates and host generalists (targeting multiple unrelated ants) tend to avoid the host, whereas host-specialists (typically restricted to Messor ants) were bolder, approached the host and allowed inspection. Generalists and host specialists regularly followed a host worker, unlike the other silverfish. Host aggression was extremely high toward non-ant-associated silverfish and modest to low in ant-associated groups. Surprisingly, the degree of chemical deception was not linked to host specificity as most silverfish, including facultative ant associates, imitated the host’s CHC profile. Messor specialists retained the same CHC profile as the host after moulting, in contrast to a host generalist, suggesting an active production of the cues (chemical mimicry). Host generalist and facultative associates flexibly copied the highly different CHC profiles of alternative host species, pointing at passive acquisition (chemical camouflage) of the host’s odour. Conclusions Overall, we found that behaviour that seems to facilitate the integration in the host colony was more pronounced in host specialist silverfish. Chemical deception, however, was employed by all ant-associated species, irrespective of their degree of host specificity.

The discovery of several members of the genus Coletinia Wygodzinsky, 1980, from subterranean habitats (endogean and troglobiont), prompted the review of this genus in the Iberian Peninsula. Most of the samples came from caves of the Mediterranean basin of Spain, from Cádiz to the Tarragona province. As a result of this revision, nine new species have been established: C. herculea n. sp., an endogean from Cádiz; C. vergitana n. sp. from the Gádor calcareous mountains in Almería; C. calaforrai n. sp. from the gypsum karst in Almería; C. intermedia n. sp. from caves in Murcia and Alicante; C. diania n. sp., found in the north of the province of Alicante; C. longitibia n. sp. and C. tessella n. sp., both troglobites from Valencia; C. redetecta n. sp. from Castellón caves and finally C. hernandoi n. sp., an endogean from Tarragona. Moreover, Coletinia maggii (Grassi, 1887) is reported for the first time in the Iberian Peninsula, and new data are presented regarding C. mendesi, C. tinautiand C. capolongoi that widen their geographic distribution and enhance the information about their anatomic characteristics and biology. These results increase the number of known species of this genus to 14 in the region and to 21 in the world. The new species are described and compared with the most closely related previously known species of the genus. Characters with the most taxonomic relevance are discussed using optical and scanning microscope studies. A key for the identification of the Iberian Coletinia species and a distribution map including all of them are also provided.

1. A diverse group of arthropods have adapted to the niches found inside the nests of social insects. Studies mostly focused on very specialised parasites residing in the brood chambers. However, the biology and strategies of symbionts occupying other niches, such as waste dumps, are underexplored.2. Using a series of complementary experiments, this study demonstrated that the Mediterranean beetle Oochrotus unicolor has adapted to the waste dump niche found in the nests of Messor harvester ants.3. Laboratory experiments confirmed field observations that the beetle preferentially resided in the refuse pits. Next, it was shown that the beetles readily consumed seeds and flour, whereas other food sources were poorly accepted and ant brood was never even eaten. The beetles did not elicit a strong aggression response in Messor ants, and they could tolerate very high densities of workers without clear costs. The beetles modestly mimicked the nest recognition cues of their Messor host. This imperfect mimicry could promote the adoption of the beetle in the ant colony, in concert with mechanical defence generated by its tank-like body. Isolation of the beetle from its host did not significantly affect the beetle's chemical cuticular profile nor did it provoke elevated ant aggression, indicating that the beetle does not acquire the chemicals passively from its host.4. This paper discusses the fact that waste dumps in social insect nests are hotspots for arthropod symbionts. It shows that symbionts in this niche may employ behavioural, trophic and chemical strategies that are different from those found in other niches of social insect nests.

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