1 INTRODUCTION
Sex
was found to be an important factor that influences gut microbiota
(Costello, Stagaman, Dethlefsen, Bohannan, & Relman, 2012; Koren et
al., 2012) that formed by long-term coevolution between host and
microorganism (Matijasic et al., 2020). Female and male insects exhibit
different ecological behaviors in terms of nutritional and dispersal
capabilities (Minard, Mavingui & Moro, 2013; Rani, Sharma, Rajagopal,
Adak & Bhatnagar, 2009), which lead to different gut microbiota
community in host. For instance, Foster (1995) and Zouache
et
al. (2011) considered that male mosquitoes disperse less than female
which could be a factor constraining bacterial diversity, Ng, Stat,
Bunce, & Simmons (2018) proved that reduced exposure to diverse
environmental microbiota could decrease in gut bacterial diversity of
insect. Minard et al. (2013) found the different nutritional
requirements between two sexes of mosquitos affect bacterial microbiota
composition (e.g., higher relative abundance of Firmicutes and
Firmicutes/Bacteroides (F/B) ratio, which contributed to nutritional
efficiency (Wan et al., (2020). As a result, bacteria from generaBacillus and Staphylococcus were detected in male
mosquitos, whereas Cryseobacterium , Pseudomonas andSerratia were present exclusively in female mosquitos (Rani,
Sharma, Rajagopal, Adak & Bhatnagar, 2009). Moreover, Wan et al. (2020)
argued
that
higher gut bacterial diversity in female might contribute to the
vertical transmission. Although many spider species show dramatically
different activity habits between the two sexes, which results in
different mobility and foraging opportunities (Aisenberg & Peretti,
2011), however, the gut microbiota of spiders influenced by sex was
almost ignored.
Spiders
are key predators in agro-forestry ecosystem (Nyffeler & Birkhofer,
2017).
However, knowledge about the gut microbial community of spiders still
limited. Hu et al. (2019) and Kumar et al. (2020) studied the diversity
and composition of
gut
microbiota from a few spider species.
Kennedy et al. (2020) suggested
that gut microbiota in Badumna longinqua (Desidae) is dictated by
the consumed prey, and the different prey taxa may remodel the gut
microbiota in drastically different ways. Hu (2019) and Sheffer et al.
(2019) compared the tissue- and population-level microbiota of some
spiders. It is noteworthy that only Hu (2019) who studied gut microbiota
influenced by sex. However, dissimilarity to previous results found from
insects, Hu (2019) showed that bacterial microbiota has no significantly
different between female and male of three spider species, includingEriovixia cavaleriei (Araneidae), Larinioides cornutus(Araneidae) and Pardosa pseudoannulata (Lycosidae), which
catapulted the necessity of gathering gut microbiota data between two
sexes of spiders.
The
wolf spiderPardosa
astrigera L.
Koch
1878 is a wandering spider widely distributed throughout terrestrial
environments, including agricultural lands in East Asia (World Spider
Catalog, 2021). It is a very active ground-dwelling predator and
dominant in most part of China. As a generalist predator, it plays a
very important role in pest control in farmland ecosystem (e.g., it is
an important natural enemy of Plutella xylostella(Plutellidae) on both cabbage and oilseed rape) (Quan, Wu, Zhou, Yun, &
Jian, 2011). Great behavioral differences between female and maleP. astrigera during the breeding period are reported, the female
usually adopt a “sit and wait” strategy waiting for the male, to avoid
the reduction of energy and being preyed by natural enemies, whereas the
male are very active to look for female everywhere (Chen & Song,
1999).
Thus, P. astrigera is a good agent while studying the effects of
sex on gut microbiota. Therefore, we investigated the gut bacterial
community of female and male P . astrigera by
high-throughput sequencing. For this, in particular, we focused on two
questions: (i) are diversity of gut bacteria in male P .astrigera higher than in the female; and (ii) are dominant gut
microbiota related to their metabolic function of energy demand
differences between the two sexes?