Analisis dan Simulasi Model Matematika untuk Kehidupan Sosial dan Dominasi dalam Koloni Semut Leptothorax Acervorum

Semut Leptothorax acervorum memiliki karakteristik kehidupan sosial, diantaranya pembagian peran, keharmonisan, dan kompetisi betina-betina dalam perebutan hak reproduksi di koloninya. Kompetisi yang mematikan ini terjadi baik sesama gyne maupun gyne dengan pekerja. Berdasarkan fenomena yang terjadi pada koloni semut Leptothorax acervorum akan dibangun model matematika. Model ini dibentuk dengan membagi populasi semut menjadi tiga kompartemen, yaitu gyne, pekerja, dan jantan pada populasi Leptothorax acervorum. Fenomena yang menarik seperti kompetisi-kompetisi yang terjadi pada semut Leptothorax acervorum dianalisis dan kestabilan koeksistensi juga akan ditunjukkan secara analitik. Selanjutnya, untuk melihat pengaruh kompetisi terhadap koeksistensi dalam koloni akan ditunjukkan dengan simulasi numerik.

Age and ovarian development are related to worker personality and task allocation in the ant Leptothorax acervorum

In social insects, workers of different morphological castes and age are known to act differently. Yet, it is unclear how body size and ovarian development influence worker personalities (i.e. consistent behavioral variation) and task allocation in similar aged ant workers of monomorphic species. Behavioral variation is thought to be a key element of division of labor, but few studies have linked worker personality to task allocation. We investigated individual behavior in Leptothorax acervorum ant workers at two time points during the first three months of their life and in two different settings. We observed worker behavior in the nest (i.e. task allocation) and in standardized aggression, exploration and brood care experiments (i.e. personality) and found behavioral repeatability in foraging and exploration. Further, workers acted consistently across settings: workers with a more aggressive and exploratory personality type were more active in the nest. Moreover, ovarian development was associated with worker personality and task allocation: older workers with well-developed ovaries foraged less, but were more aggressive and exploratory. In accordance with the typical age-polyethism of social insects, workers became more active and foraged more as they grew older. Consequently, our study suggests that task allocation in Leptothorax acervorum is not only influenced by ovarian development and age, but moreover by the personalities of its workers.

Cooperation of Nature and Physiologically Inspired Mechanisms in Visualisation

A novel approach of integrating two swarm intelligence algorithms is considered, one simulating the behaviour of birds flocking (Particle Swarm Optimisation) and the other one (Stochastic Diffusion Search) mimics the recruitment behaviour of one species of ants – Leptothorax acervorum. This hybrid algorithm is assisted by a biological mechanism inspired by the behaviour of blood flow and cells in blood vessels, where the concept of high and low blood pressure is utilised. The performance of the nature-inspired algorithms and the biologically inspired mechanisms in the hybrid algorithm is reflected through a cooperative attempt to make a drawing on the canvas. The scientific value of the marriage between the two swarm intelligence algorithms is currently being investigated thoroughly on many benchmarks, and the results reported suggest a promising prospect (al-Rifaie, Bishop & Blackwell, 2011). It may also be discussed whether or not the artworks generated by nature and biologically inspired algorithms can possibly be considered as computationally creative.

Workers influence royal reproduction

Understanding which parties regulate reproduction is fundamental to understanding conflict resolution in animal societies. In social insects, workers can influence male production and sex ratio. Surprisingly, few studies have investigated worker influence over which queen(s) reproduce(s) in multiple queen (MQ) colonies (skew), despite skew determining worker-brood relatedness and so worker fitness. We provide evidence for worker influence over skew in a functionally monogynous population of the ant Leptothorax acervorum . Observations of MQ colonies leading up to egg laying showed worker aggressive and non-aggressive behaviour towards queens and predicted which queen monopolized reproduction. In contrast, among-queen interactions were rare and did not predict queen reproduction. Furthermore, parentage analysis showed workers favoured their mother when present, ensuring closely related fullsibs (average r = 0.5) were reared instead of less related offspring of other resident queens ( r ≤ 0.375). Discrimination among queens using relatedness-based cues, however, seems unlikely as workers also biased their behaviour in colonies without a mother queen. In other polygynous populations of this species, workers are not aggressive towards queens and MQs reproduce, showing the outcome of social conflicts varies within species. In conclusion, this study supports non-reproductive parties having the power and information to influence skew within cooperative breeding groups.