Migration control: a distance compensation strategy in ants

Migratory behaviour forms an intrinsic part of the life histories of many organisms but is often a high-risk process. Consequently, varied strategies have evolved to negate such risks, but empirical data relating to their functioning are limited. In this study, we use the model system of the house-hunting ant Temnothorax albipennis to demonstrate a key strategy that can shorten migration exposure times in a group of social insects. Colonies of these ants frequently migrate to new nest sites, and due to the nature of their habitat, the distances over which they do so are variable, leading to fluctuating potential costs dependent on migration parameters. We show that colonies of this species facultatively alter the dynamics of a migration and so compensate for the distance over which a given migration occurs. Specifically, they achieve this by modulating the rate of ‘tandem running’, in which workers teach each other the route to a new nest site. Using this method, colonies are able to engage a larger number of individuals in the migration process when the distance to be traversed is greater, and furthermore, the system appears to be based on perceived encounter rate at the individual level. This form of decentralised control highlights the adaptive nature of a behaviour of ecological importance, and indicates that the key to its robustness lies in the use of simple rules. Additionally, our results suggest that such coordinated group reactions are central to achieving the high levels of ecological success seen in many eusocial organisms

Differentiated anti-predation responses in a superorganism

© 2015 O'Shea-Wheller et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Insect societies are complex systems, displaying emergent properties much greater than the sum of their individual parts. As such, the concept of these societies as single 'superorganisms' is widely applied to describe their organisation and biology. Here, we test the applicability of this concept to the response of social insect colonies to predation during a vulnerable period of their life history. We used the model system of house-hunting behaviour in the ant Temnothorax albipennis.We show that removing individuals from directly within the nest causes an evacuation response, while removing ants at the periphery of scouting activity causes the colony to withdraw back into the nest. This suggests that colonies react differentially, but in a coordinated fashion, to these differing types of predation. Our findings lend support to the superorganism concept, as the whole society reacts much like a single organism would in response to attacks on different parts of its body. The implication of this is that a collective reaction to the location of worker loss within insect colonies is key to avoiding further harm, much in the same way that the nervous systems of individuals facilitate the avoidance of localised damage

A large-scale study of <em>Varroa destructor</em> treatment adherence in apiculture

\ua9 2025 The authors. Adherence to treatment regimens is a key predictor of prognostic outcomes in clinical and veterinary medicine. Despite this, a paucity of data exists regarding adherence practices in apiculture, a setting in which the use of preventative and therapeutic medications is widespread. This is especially pertinent when considering management of the ectoparasite Varroa destructor, which remains the primary health concern faced by beekeepers globally. In order to be effective, Varroa treatments must be applied to colonies during defined periods, corresponding to key etiological junctures in the mite’s life-cycle. Failure to adhere to treatment guidelines can thus adversely influence treatment efficacy, however the scope of this issue is poorly understood. Here, utilising data collected from a national annual survey of beekeepers in England and Wales, we explore the relative impact of Varroa treatment adherence upon colony health outcomes. Results demonstrate that lower overwinter colony losses are predicted by correct treatment temporality, but not by product application alone, supporting the epidemiological significance of application timing. Notably, our data also indicate that over one third of beekeepers engaged in at least some level of non-adherence, highlighting the ubiquity of the issue. These findings suggest that Varroa treatment non-adherence is a substantial driver of large-scale colony mortality, and indicate that further work is needed to elucidate its underlying causes

A social mechanism facilitates ant colony emigrations over different distances

Behavioural responses enable animals to react rapidly to fluctuating environments. In eusocial organisms, such changes are often enacted at the group level, but may be organised in a decentralised fashion by the actions of individuals. However, the contributions of different group members are rarely homogenous, and there is evidence to suggest that certain ‘keystone’ individuals are important in shaping collective responses. Accordingly, investigations of the dynamics and structuring of behavioural changes at both the group and individual level, are crucial for evaluating the relative influence of different individuals. Here, we examine the composition of tandem running behaviour during colony emigrations in the ant species Temnothorax albipennis. Tandem running is modulated in response to emigration distance, with more runs being conducted when a more distant nest site must be reached. We show that certain individuals are highly active in the tandem running process, attempting significantly more work in the task. Contrary to expectations, however, such individuals are in fact no more successful at conducting tandem runs than their less active nest mates. Instead, it seems that when more tandem runs are required, colonies rely on greater recruitment of workers into the process. The implications of our study are that in some cases, even when apparently ‘key’ individuals exist within a group, their relative contribution to task performance may be far from decisive.</jats:p

Interlaboratory validation of an optimized protocol for measuring α-amylase activity by the INFOGEST international research network

The activity of α-amylases is frequently determined using a single-point assay at 20 °C. Previous work within INFOGEST “Working Group 5 - Starch digestion and amylases” identified significant interlaboratory variation with this protocol. The current study aimed to evaluate the repeatability (intralaboratory precision) and reproducibility (interlaboratory precision), measured as coefficients of variation (CVs), of a newly optimized protocol version based on four time-point measurements at 37 °C. Human saliva (a pool from ten healthy adults) and three porcine enzyme preparations (two pancreatic α-amylases and pancreatin) were tested in 13 laboratories across 12 countries and 3 continents. Assay repeatability for each lab remained below 20% for all test products and the overall repeatability was below 15%, ranging between 8 and 13% for all products. Reproducibility was greatly improved with interlaboratory CVs ranging from 16 to 21%, i.e. up to four times lower than with the original method. Five laboratories repeated the same assay at 20 °C, and the amylolytic activity of each product increased by 3.3-fold (± 0.3) from 20 to 37 °C. The newly optimized protocol is henceforth recommended to ensure precise determinations of α-amylase activity levels and to facilitate comparisons across different studies

Diagnosis and management of postoperative pulmonary hypertensive crisis.

In this paper we discuss two infants and one child who experienced a previously unreported complication after complete correction of a large, unrestrictive ventricular septal defect. Two patients had documented pulmonary hypertensive crises and severe right-heart failure secondary to hypoxia and pulmonary vasoconstriction. These crises were associated with significantly increased right ventricular (RV) peak systolic and end-diastolic pressures and right-to-left shunting via a foramen ovale which, in turn, exaggerated the hypoxis. The crises were treated successfully with tolazoline in the second and third patients. RV pressure returned to normal values and have remained normal up to 12 months postoperatively in the second patient. Although the RV pressures decreased with tolazoline in the third patient, they never reached normal values. Postoperative monitoring of pulmonary artery and RV pressures in infants with large ventricular septal defects is essential when unexplained complications are encountered. Tolazoline proved to be very effective in the treatment of two patients with pulmonary vasoconstriction secondary to hypoxia.</jats:p

Mean percentage of total colony workers in nests at final time points (at 120 min).

<p>The mean represents ants in the good nests (n = 10 colonies) for the control, nest predation and peripheral predation groups and ants in both nests (n = 11 colonies) for the nest destruction group (from previously published data). Significant pair-wise comparisons between treatment group means are marked with asterisks (*-P<0.05, **-P<0.01, ***-P<0.001) other comparisons are not significant. Error bars indicate 95% confidence intervals.</p