Principles of Insect Path Integration

Abstract

Continuously monitoring its position in space relative to a goal is one of the most essential tasks for an animal that moves through its environment. Species as diverse as rats, bees, and crabs achieve this by integrating all changes of direction with the distance covered during their foraging trips, a process called path integration. They generate an estimate of their current position relative to a starting point, enabling a straight-line return, following what is known as a home vector. While in theory path integration always leads the animal precisely back home, in the real world noise limits the usefulness of this strategy when operating in isolation. Noise results from stochastic processes in the nervous system and from unreliable sensory information, particularly when obtaining heading estimates. Path integration, during which angular self-motion provides the sole input for encoding heading (idiothetic path integration), results in accumulating errors that render this strategy useless over long distances. In contrast, when using an external compass this limitation is avoided (allothetic path integration). Many navigating insects indeed rely on external compass cues for estimating body orientation, whereas they obtain distance information by integration of steps or optic-flow-based speed signals. In the insect brain, a region called the central complex plays a key role for path integration. Not only does the central complex house a ring-attractor network that encodes head directions, neurons responding to optic flow also converge with this circuit. A neural substrate for integrating direction and distance into a memorized home vector has therefore been proposed in the central complex. We discuss how behavioral data and the theoretical framework of path integration can be aligned with these neural data.

Differential investment in brain regions for a diurnal and nocturnal lifestyle in Australian Myrmecia ants

“…The central complex is a highly conserved region that has been identified to be vital for processing spatial information, controlling locomotion and orientation, and integrating multisensory information (Heinze, 2017;Heinze et al, 2018;Pfeiffer & Homberg, 2014;Seelig & Jayaraman, 2015;Stone et al, 2017;Strauss & Heisenberg, 1993). It is perhaps because the function of the central complex is integral to the performance of many fundamental behaviors that its size did not vary between the diurnal and nocturnal species (Figure 8).…”

Path integration error and adaptable search behaviors in a mantis shrimp

“…If directional information is measured in relation to a stable compass heading or environmental feature, angular errors would be of a lesser magnitude than if angular information is measured from a previous rotational estimate, which would compound over the course of an animal’s journey. Some models of error accumulation during path integration suggest that due to this large accumulated rotational error, path integration over extended distances (such as those exhibited by bees and ants) would require the use of a stable compass reference during navigation (Cheung et al, 2007; Cheung and Vickerstaff, 2010; Heinze et al, 2018). This may be true for mantis shrimp as well; however, previous work suggests that mantis shrimp do rely on idiothetic orientation during path integration when celestial cues are obscured (Patel and Cronin, 2020).…”

Dynamic multimodal interactions in navigating wood ants: What do path details tell us about cue integration?

“…Such solitarily foraging ants rely on path integration (PI) and learnt information from the environment. PI is an innate behaviour that allows individuals to explore unfamiliar terrain while being safely connected to their nest (Heinze et al 2018; Collett 2019). As ants become familiar with an environment, they also learn and use visual and olfactory information to guide routes (visual: (Collett et al 1992; Kohler & Wehner 2005; Graham & Collett 2006; Wystrach et al 2011; Mangan & Webb 2012), olfactory: (Buehlmann et al 2015)) and drive searches for the nest (visual: (Wehner & Räber 1979; Wehner et al 1996; Narendra et al 2007), olfactory: (Steck 2012)) or a familiar feeder (visual: (Durier et al 2003; Collett et al 2014; Buehlmann et al 2016), olfactory: (Huber & Knaden 2018)).…”