1 Introduction
The Chinese mole shrew (Anourosorex squamipes Milne-Edwards,
1872) is a small insectivore mammal (He et al. 2016; Hoffmann 1987;
Motokawa. et al. 2003), distributed in southwestern China and adjacent
areas (He et al. 2016; Motokawa and Lin 2002; Motokawa. et al. 2003;
Wilson et al. 2018). Like other house shrews (Khanam et al. 2016),A. squamipes is regarded as a pest in the agricultural ecosystem
(Peng et al. 2018; Zong et al. 2017), causing both direct and indirect
effects (Mdangi et al. 2013). As is widely known, synanthropic species
association with human habitats widely impact agriculture and human
health through damage to crops and transmission of pathogens (Khanam et
al. 2016; Palis et al. 2007). The Chinese mole shrew affects crops and
human health in China in a multitude of ways (Peng et al. 2018; Yang et
al. 2013). For example, this shrew species consumes and contaminates
stored grains and crops (Peng et al. 2018). In addition, it is
considered to be a potential source of various types of viruses and
pathogens (Gu et al. 2016; Song et al. 2007). A. squamipes caused
severe damages to crops resulting from increased population sizes in
Southwest China, especially in Sichuan Basin (Yang et al. 2013; Zong et
al. 2017). Moreover, due to their peculiar food and foraging habits,
existing rodent control practices are not suitable for controlling the
number of these shrews, resulting in grain insecurity and
reduced
villager livelihoods.
Diet analysis are important for understanding how animal populations
respond to resource distribution and variety as well as how to manage
them (Gordon et al. 2019). Dietary information has been used in addition
to pure feeding ecology in a variety of applied studies (Gong et al.
2017). Accurate identification of foods is a prerequisite to fully
understanding the feeding ecology of a species and effectively
controlling pest numbers (Heroldova et al. 2008). Better understanding
of the feeding habits
of house shrews can help to evaluate how growing
populations of A. squamipes affect human and agricultural systems
even during resource-poor seasons and develop more effective pests
management strategies, including targeted baits
and lures (Khanam et al.
2016; Lathiya et al. 2008).
However, very few studies have described
the composition and seasonal variations in the Chinese mole shrew diet
with higher taxonomic resolution.
For natural populations, it is difficult to accurately and efficiently
assess wildlife diets, because of their elusive predatory behaviors and
versatile feeding habits (Gong et al. 2017; Ozaki et al. 2018).
Identifying food items with the highest taxonomic resolution is nearly
impossible with traditional microhistological analysis of gut contents
and stable isotope analysis (Jeunen et al. 2019; Murray et al. 2016;
Rytkonen et al. 2019). A major limitation of the classical observational
methods is that foods items are often digested to a greater extent,
making identification of their remains taxonomically challenging (Berry
et al. 2017; Bessey et al. 2019). Especially in the cases of
insectivorous predators, whose prey is variable, small in size, and
easily disintegrated in the gut, direct identification is difficult
since their chyme contains a
mixture of degraded prey fragments (Clare
et al. 2014; Rytkonen et al. 2019). Besides, the stable isotope approach
is unable to distinguish prey at the species level (Bohmann et al.
2018). Therefore, a broad-spectrum technique with higher taxonomic
resolution is necessary because shrew species have highly diverse and
flexible diets that include insects, annelids, and plants (Churchfield
et al. 2012; Churchfield et al. 2010; Haberl 2002).
Here, DNA metabarcoding enabled us to identify food DNA (including
highly degraded DNA) in gut contents or fecal samples with higher
taxonomic resolution (Kartzinel and Pringle 2015; Pompanon et al. 2012).
To date, among shrew species, only the diets of Asian musk shrew
(Suncus murinus ) have been examined through DNA metabarcoding
methods (Brown et al. 2014; Khanam et al. 2016). Most previous studies
(Churchfield et al. 2012; Churchfield et al. 2010; De Pascual and De
Ascencao 2000; Haberl 2002; McCay and Storm 1997) that assessed diets in
shrew species are based on microhistological identification of insect
fragments in stomach contents or fecal pellets, resulting in large
proportions of poorly resolved plant taxa and dietary information mainly
at higher taxonomic levels. Little is known about the invertebrate prey
species and plants (especially at the species-level) consumed by Chinese
mole shrew, which prevents understanding of their feeding ecology and
thus impedes effective pest control.
In this study, we attempted to characterize the Chinese mole shrew diet
across the four seasons by DNA metabarcoding of stomach samples. We
compared dietary richness and composition across seasons to evaluate the
impacts of this pest on crops and enhance our understanding of dietary
breadth and seasonal food preferences in A. squamipes . Thus, this
study may have implications for food niche and management of Chinese
mole shrew as well as help to develop appropriate pest control
strategies.