Search

This research compares the global debt trends in the aftermath of the COVID-19 pandemic, focusing on economies that frame the North and South divide. The research centers on debt ratios, which serve as indicators of countries' ability to finance recovery and development projects. The study period runs from 2015 to 2022 and follows the IMF's country classification, which divides the world into advanced economies (AE) and emerging market and developing economies (EMDE). The research employs panel data regressions to assess three key debt ratios—external debt to Gross Domestic Product (GDP), external debt to exports, and public debt to GDP—against various pandemic-related indicators and control variables. The analysis provides three major contributions. Firstly, an examination of external and public debt burdens is conducted, showing that escalated external and public debt burdens in EMDE contrast with increasing public debt in AE, primarily due to fiscal stimulus. Secondly, it is argued that the ongoing pandemic has intensified the widening economic gap between the North (AE) and the south (EMDE). Thirdly, a review is presented of both orthodox and heterodox policies identified in existing literature that are considered capable of mitigating external vulnerabilities in EMDE. Findings highlight the critical need for multifaceted measures to address debt vulnerability and promote sustainable economic recovery in a post-pandemic world. [ABSTRACT FROM AUTHOR]

In flies, the olfactory information is carried from the first relay in the brain, the antennal lobe, to the mushroom body (MB) and the lateral horn (LH). Olfactory associations are formed in the MB. The LH was ascribed a role in innate responses based on the stereotyped connectivity with the antennal lobe, stereotyped physiological responses to odors, and MB silencing experiments. Direct evidence for the functional role of the LH is still missing. Here, we investigate the behavioral role of the LH neurons (LHNs) directly, using the CO2 response as a paradigm. Our results show the involvement of the LH in innate responses. Specifically, we demonstrate that activity in two sets of neurons is required for the full behavioral response to CO2. Tests of the behavioral response to other odors indicate the neurons are selective to CO2 response. Using calcium imaging, we observe that the two sets of neurons respond to CO2 in a different manner. Using independent manipulation and recording of the two sets of neurons, we find that the one that projects to the superior intermediate protocerebrum (SIP) also outputs to the local neurons within the LH. The design of simultaneous output at the LH and the SIP, an output of the MB, allows for coordination between innate and learned responses. [ABSTRACT FROM AUTHOR]

Highlights • Female sexual behavior and egg-laying are composed of numerous behavioral modules. • Mating decisions rely on the analysis of courtship song features such as the bout duration. • Fertilized females are highly selective regarding egg-laying site preference. • Egg-laying decisions rely on substrate, internal, social and predator cues. Innate responses are often sexually dimorphic. Studies of female specific behaviors have remained niche, but the focus is changing as illustrated by the recent progress in understanding the female courtship responses and egg-laying decisions. In this review, we will cover our current knowledge about female behaviors in these two specific contexts. Recent studies elucidate on how females process the courtship song. They also show that egg-laying decisions are extremely complex, requiring the assessment of food, microbial, predator and social cues. Study of female responses will improve our understanding of how a nervous system processes different challenges. [ABSTRACT FROM AUTHOR]

In insects, the role of reproductive hormones in coordinating fertility with mating activity is unclear. In this issue of Neuron , Lin et al. (2016) describe a mechanism in which juvenile hormone regulates courtship advantage of older Drosophila males by elevating the pheromone sensitivity of Or47b olfactory circuitry. [ABSTRACT FROM AUTHOR]

Courtship behaviours allow animals to interact and display their qualities before committing to reproduction. In fly courtship, the female decides whether or not to mate and is thought to display receptivity by slowing down to accept the male. Very little is known on the neuronal brain circuitry controlling female receptivity. Here we use genetic manipulation and behavioural studies to identify a novel set of neurons in the brain that controls sexual receptivity in the female without triggering the postmating response. We show that these neurons, defined by the expression of the transcription factor apterous, affect the modulation of female walking speed during courtship. Interestingly, we found that the apterous neurons required for female receptivity are neither doublesex nor fruitless positive suggesting that apterous neurons are not specified by the sex-determination cascade. Overall, these findings identify a neuronal substrate underlying female response to courtship and highlight the central role of walking speed in the receptivity behaviour. [ABSTRACT FROM AUTHOR]

Aggression is an adaptive set of behaviors that allows animals to compete against one another in an environment of limited resources. Typically, males fight for mates and food, whereas females fight for food and nest sites. 1 Although the study of male aggression has been facilitated by the extravagant nature of the ritualized displays involved and the remarkable armaments sported by males of many species, 2,3,4 the subtler and rarer instances of inter-female aggression have historically received much less attention. In Drosophila , females display high levels of complex and highly structured aggression on a food patch with conspecific females. 5,6,7,8,9 Other contexts of female aggression have not been explored. Indeed, whether females compete for mating partners, as males do, has remained unknown so far. In the present work, we report that Drosophila melanogaster females reliably display aggression toward mating pairs. This aggressive behavior is regulated by mating status and perception of mating opportunities and relies heavily on olfaction. Furthermore, we found that food odor in combination with OR47b-dependent fly odor sensing is required for proper expression of aggressive behavior. Taken together, we describe a social context linked to reproduction in which Drosophila females aspiring to mate produce consistent and stereotyped displays of aggression. These findings open the door for further inquiries into the neural mechanisms that govern this behavior. • Female fruit flies are aggressive toward mating pairs • Mating status and perception of mating opportunities modulate aggression drive • Female aggression requires the presence of food odor • Ability to sense conspecifics through OR47b modulates aggression Gaspar et al. uncover a new context of female Drosophila melanogaster aggression. They find that, in this context, the willingness of the female to mate correlates with aggression. Aggression only occurs in the presence of food odor plus a mating pair, but the ability to smell conspecifics is important to modulate it. [ABSTRACT FROM AUTHOR]

Summary: Internal state as well as environmental conditions influence choice behavior. The neural circuits underpinning state-dependent behavior remain largely unknown. Carbon dioxide (CO2) is an important olfactory cue for many insects, including mosquitoes, flies, moths, and honeybees [1]. Concentrations of CO2 higher than 0.02% above atmospheric level trigger a strong innate avoidance in the fly Drosophila melanogaster [2, 3]. Here, we show that the mushroom body (MB), a brain center essential for olfactory associative memories [4–6] but thought to be dispensable for innate odor processing [7], is essential for CO2 avoidance behavior only in the context of starvation or in the context of a food-related odor. Consistent with this, CO2 stimulation elicits Ca2+ influx into the MB intrinsic cells (Kenyon cells: KCs) in vivo. We identify an atypical projection neuron (bilateral ventral projection neuron, biVPN) that connects CO2 sensory input bilaterally to the MB calyx. Blocking synaptic output of the biVPN completely abolishes CO2 avoidance in food-deprived flies, but not in fed flies. These findings show that two alternative neural pathways control innate choice behavior, and they are dependent on the animal’s internal state. In addition, they suggest that, during innate choice behavior, the MB serves as an integration site for internal state and olfactory input. [ABSTRACT FROM AUTHOR]

Communication between male and female fruit flies during courtship is essential for successful mating, but, as with many other species, it is the female who decides whether to mate. Here, we show a novel role for ovipositor extrusion in promoting male copulation attempts in virgin and mated females and signaling acceptance in virgins. We first show that ovipositor extrusion is only displayed by sexually mature females, exclusively during courtship and in response to the male song. We identified a pair of descending neurons that controls ovipositor extrusion in mated females. Genetic silencing of the descending neurons shows that ovipositor extrusion stimulates the male to attempt copulation. A detailed behavioral analysis revealed that during courtship, the male repeatedly licks the female genitalia, independently of ovipositor extrusion, and that licking an extruded ovipositor prompts a copulation attempt. However, if the ovipositor is not subsequently retracted, copulation is prevented, as it happens with mated females. In this study, we reveal a dual function of the ovipositor: while its extrusion is necessary for initiating copulation by the male, its retraction signals female acceptance. We thus uncover the significance of the communication between male and female that initiates the transition from courtship to copulation. • DNp13 activity induces full ovipositor extrusion • Ovipositor extrusion is a response to the male courtship song • Male licking an extruded ovipositor prompts copulation attempt • Upon copulation attempt, receptive females retract the ovipositor to allow copulation Mezzera et al. uncover the significance of the communication between male and female that initiates the transition from courtship to copulation. A dual function of the fruit fly ovipositor is revealed: while its extrusion is necessary for initiating copulation by the male, its retraction signals female acceptance. [ABSTRACT FROM AUTHOR]

In flies, the olfactory information is carried from the first relay in the brain, the antennal lobe, to the mushroom body (MB) and the lateral horn (LH). Olfactory associations are formed in the MB. The LH was ascribed a role in innate responses based on the stereotyped connectivity with the antennal lobe, stereotyped physiological responses to odors, and MB silencing experiments. Direct evidence for the functional role of the LH is still missing. Here, we investigate the behavioral role of the LH neurons (LHNs) directly, using the CO2 response as a paradigm. Our results show the involvement of the LH in innate responses. Specifically, we demonstrate that activity in two sets of neurons is required for the full behavioral response to CO2. Tests of the behavioral response to other odors indicate the neurons are selective to CO2 response. Using calcium imaging, we observe that the two sets of neurons respond to CO2 in a different manner. Using independent manipulation and recording of the two sets of neurons, we find that the one that projects to the superior intermediate protocerebrum (SIP) also outputs to the local neurons within the LH. The design of simultaneous output at the LH and the SIP, an output of the MB, allows for coordination between innate and learned responses., Competing Interests: The authors have declared that no competing interests exist.

Internal state as well as environmental conditions influence choice behavior. The neural circuits underpinning state-dependent behavior remain largely unknown. Carbon dioxide (CO2) is an important olfactory cue for many insects, including mosquitoes, flies, moths, and honeybees [1]. Concentrations of CO2 higher than 0.02% above atmospheric level trigger a strong innate avoidance in the fly Drosophila melanogaster [2, 3]. Here, we show that the mushroom body (MB), a brain center essential for olfactory associative memories [4-6] but thought to be dispensable for innate odor processing [7], is essential for CO2 avoidance behavior only in the context of starvation or in the context of a food-related odor. Consistent with this, CO2 stimulation elicits Ca(2+) influx into the MB intrinsic cells (Kenyon cells: KCs) in vivo. We identify an atypical projection neuron (bilateral ventral projection neuron, biVPN) that connects CO2 sensory input bilaterally to the MB calyx. Blocking synaptic output of the biVPN completely abolishes CO2 avoidance in food-deprived flies, but not in fed flies. These findings show that two alternative neural pathways control innate choice behavior, and they are dependent on the animal's internal state. In addition, they suggest that, during innate choice behavior, the MB serves as an integration site for internal state and olfactory input., (Copyright © 2013 Elsevier Ltd. All rights reserved.)