Panic buying? Food hoarding during the pandemic period with city lockdown

Food hoarding is prevalent during the COVID-19 pandemic.To investigate the mechanism of urban consumers’food hoarding behaviors,we categorize hoarding motives into rational and irrational ones.Using random online survey samples from three cities in China,we employ the multivariate probit model to investigate the rational and irrational motives on food hoarding behavior.Our results confirmed the existence of both rational and irrational food hoarding,and also found factors attributing to the different buying behaviors.The amount of food at hand and the expectation on the infection possibility of COVID-19 are two major factors affecting rational hoarding.Bad mood and herd psychology are factors contributing to panic buying.This study provides an empirical evidence to support intervention policies aiming at mitigating panic buying behavior.

Asymmetric competition for seeds between two sympatric food hoarding rodents:implications for coexistence

Asymmetric competition occurs when some species have distinct advantages over their competitors and is common in animals with overlapping habitats and diet.However,the mechanism allowing coexistence between asymmetric competitors is not fully clear.Chinese white-bellied rats(Niviventer confucianus,CWR)and Korean field mice(Apodemus peninsulae,KFM)are common asymmetric competitors in shrublands and forests west of Beijing city.They share similar diet(e.g.plant seeds)and activity(nocturnal),but differ in body size(CWR are bigger than KFM),food hoarding habit(CWR:mainly larder hoarding;KFM:both larder and scatter hoarding),and ability to protect cached food(CWR are more aggressive than KFM).Here,we tested seed competition in 15 CWR-KFM pairs over a 10-day period under semi-natural enclosure conditions to uncover the differences in food hoarding,cache pilferage,and food protection between the 2 rodents,and discuss the implication for coexistence.Prior to pilferage,CWR harvested and ate more seeds than KFM.CWR tended to larder hoard seeds,whereas KFM preferred to scatter hoard seeds.Following pilferage,CWR increased consumption,decreased intensity of hoarding,and pilfered more caches from KFM than they lost,while KFM increased consumption more than they hoarded,and they preferred to hoard seeds in low and medium competition areas.Accordingly,both of the 2 rodent species increased their total energy consumption and hoarding following pilferage.Both rodent species tended to harvest seeds from the source,rather than pilfer caches from each other to compensate for cache loss via pilferage.Compared to CWR,KFM consumed fewer seeds when considering seed number,but hoarded more seeds when considering the seeds’relative energy(energy of hoarded seeds/rodent body mass2/3)at the end of the trials.These results suggest that asymmetric competition for food exists between CWR and KFM,but differentiation in hoarding behavior could help the subordinate species(i.e.KFM)hoard more energy than the dominant species(i.e.CWR),and may contribute to their coexistence in the field.

Effects of rodent abundance and richness on cache pilfering

Scatterhoarding is a common behavioral strategy to conserve food during periods of scarcity,but this type of food storage is vulnerable to theft or pilferage.A variety of environmental factors and cache characteristics influence the rate of pilferage.Here we investigate 2 environmental factors,which heretofore have not received much attention:the abundance and species richness of scatterhoarding animals in the vicinity of scatterhoarded seeds.We measured the rate of cache pilferage at 7 sites that differed in the number and species composition of granivorous rodents in western Nevada using local native seeds and sunflower seeds.We found that there was no difference between the pilferage rate of native seeds and sunflower seeds,but that sites with different rodent abundances had different pilferage rates.Pilferage rates were proportional to the abundance of scatterhoarding rodents.Scatterhoarding rodents removed seeds at the rate of 1.3%/day/rodent individual.Species richness of scatterhoarding rodents was not correlated with rates of pilferage.These results suggest that density-dependent competition for scatterhoarded seeds is a strong determinant of pilferage rates.

Visual and auditory cues facilitate cache pilferage of Siberian chipmunks(Tamias sibiricus)under indoor conditions

In the struggle for survival,scatter-hoarding rodents are known to cache food and pilfer the caches of others.The extent to which rodents utilize auditory/visual cues from conspecifics to improve cache-pilfering is un­known.Here,Siberian chipmunks(Tamias sibiricus)were allowed to search for caches of Corylus heterophyl­la seeds(man-made caches and animal-made caches)after experiencing cues from a conspecific’s cache-search­ing events.For each type of cache,3 experimental scenarios were presented:(1)alone(control);(2)auditory/visual(hearing and seeing conspecific’s cache-searching events);and(3)auditory only(hearing conspecific’s cache-searching events only)with random orders.The subjects located man-made caches faster,harvested more caches,and hoarded more seeds both in the auditory/visual and the auditory only treatments compared to the control,while scatter-hoarding more seeds in the auditory/visual treatment but larder-hoarding more seeds in the auditory only treatment.Compared to the control,the animals spent less time locating animal-made caches,har­vested more caches,ate fewer seeds,larder-hoarded more seeds and hoarded more seeds in total both in the au­ditory/visual and the auditory only treatments,while eating more seeds and hoarded fewer seeds in total in the auditory only treatment than in the auditory/visual treatment.The results also show that females spent less time locating the animal-made caches,but they scatter-hoarded fewer seeds than males in the auditory/visual treat­ment.To the best of our knowledge,this is the first report that visual and/or auditory cues of conspecifics im­prove cache-pilfering and hoarding in rodents.