Sex differences in how territory quality affects aggression in convict cichlids

In animal contests, the value an individual assigns to limited resources can directly impact the level of aggression they demonstrate. For territorial species, individuals often assess their territory quality and appropriately modify the time and energy invested in its defense. In this study, male and female convict cichlids, Amatitlania nigrofasciata, were acclimated to one of three territorial treatments representing either a Low, Medium, or High resource value. Territories with a “Low Value” included substrate alone, “Medium Value” territories included substrate and a nest site, and a “High Value” territory included substrate, a nest site, and constant food source. After three days of acclimation, a size-matched intruder was introduced to elicit territorial aggression and behaviors were observed. Territory quality affected one measure of low-intensity aggression (displays) in residents but had no effect on high-intensity aggression (bites and chases). Moreover, there was a significant effect of sex, with males and females differing in the types of aggressive behaviors demonstrated across all treatments. Females showed more low-intensity aggressive behaviors toward intruders than males did. Additionally, a significant interaction of sex and territory quality was observed on two measures of high-intensity aggressive behavior (bites and chases), with females more likely than males to increase aggressive behaviors along with increasing territory quality. This suggests that females may be more sensitive and/or responsive to changes in the quality of a territory, possibly due to the necessity of a suitable nest site for egg deposition within a territory.

Chemogenetic modulation of histaminergic neurons in the tuberomamillary nucleus alters territorial aggression and wakefulness

Designer receptor activated by designer drugs (DREADDs) techniques are widely used to modulate the activities of specific neuronal populations during behavioural tasks. However, DREADDs-induced modulation of histaminergic neurons in the tuberomamillary nucleus (HATMN neurons) has produced inconsistent effects on the sleep–wake cycle, possibly due to the use of Hdc-Cre mice driving Cre recombinase and DREADDs activity outside the targeted region. Moreover, previous DREADDs studies have not examined locomotor activity and aggressive behaviours, which are also regulated by brain histamine levels. In the present study, we investigated the effects of HATMN activation and inhibition on the locomotor activity, aggressive behaviours and sleep–wake cycle of Hdc-Cre mice with minimal non-target expression of Cre-recombinase. Chemoactivation of HATMN moderately enhanced locomotor activity in a novel open field. Activation of HATMN neurons significantly enhanced aggressive behaviour in the resident–intruder test. Wakefulness was increased and non-rapid eye movement (NREM) sleep decreased for an hour by HATMN chemoactivation. Conversely HATMN chemoinhibition decreased wakefulness and increased NREM sleep for 6 h. These changes in wakefulness induced by HATMN modulation were related to the maintenance of vigilance state. These results indicate the influences of HATMN neurons on exploratory activity, territorial aggression, and wake maintenance.

Hierarchies, population control, war

FM Annukka Sailon tieteiden ja aatteiden historian alaan kuuluva väitöskirja "Hierarchies, population control, war: Debating territorial aggression in behavioral sciences (1965–75)" tarkastettiin Oulun yliopistossa 30.10.2020. Vastaväittäjänä toimi professori Erika Milam (Princetonin yliopisto) ja kustoksena professori Petteri Pietikäinen (Oulun yliopisto). Tilaisuus oli englanninkielinen ja järjestettiin etäyhteyksin.

India and Vietnam in the Indo-Pacific

The international order today is characterised by power shift and increasing multipolarity. Countries such as India and Vietnam are working to consolidate the evolving multipolarity in the Indo-Pacific. The article maps the convergences in the Indian and Vietnamese foreign policy strategies and in their approaches to the Indo-Pacific. Both countries confront similar security challenges, such as creeping territorial aggression. Further, India and Vietnam are collaborating with the United States and Japan to maintain a favourable balance of power in the Indo-Pacific. While Delhi and Hanoi agree on the need to reform the United Nations, there is still some distance to travel to find a common position on regional economic architectures. The India–Vietnam partnership demonstrates that nation-states will seek to define the structure of the international order and in this instance by increasing the intensity of multipolarity.

Chemogenetic modulation of histaminergic neurons in the tuberomammillary nucleus alters territorial aggression and wakefulness

Designer receptor activated by designer drugs (DREADDs) techniques are widely used to modulate the activities of specific neuronal populations during behavioural tasks. However, DREADDs-induced modulation of histaminergic neurons in the tuberomammillary nucleus (HATMN neurons) has produced inconsistent effects on the sleep–wake cycle, possibly due to the use of Hdc-Cre mice driving Cre recombinase and DREADDs activity outside the targeted region. Moreover, previous DREADDs studies have not examined locomotor activity and aggressive behaviours, which are also regulated by brain histamine levels. In the present study, we investigated the effects of HATMN activation and inhibition on the locomotor activity, aggressive behaviours and sleep–wake cycle of Hdc-Cre mice with minimal non-target expression of Cre-recombinase. Chemoactivation of HATMN moderately enhanced locomotor activity in a novel open field. Activation of HATMN neurons significantly enhanced aggressive behaviour in the resident–intruder test. Wakefulness was increased and non-rapid eye movement (NREM) sleep decreased for an hour by HATMN chemoactivation. Conversely HATMN chemoinhibition decreased wakefulness and increased NREM sleep for 6 hours. These changes in wakefulness induced by HATMN modulation were related to vigilance status transition. These results indicate the influences of HATMN neurons on exploratory activity, territorial aggression, and wake maintenance.