DOI: 10.5061/dryad.41ns1rnnc
title: Data for: Biomechanical adaptations enable phoretic mite species to occupy distinct spatial niches on host burying beetles

description: Niche theory predicts that ecologically similar species coexist by
 minimising interspecific competition through niche partitioning. Therefore
 understanding the mechanisms of niche partitioning is essential for
 predicting interactions and coexistence between competing organisms. Here
 we study two phoretic mite species, Poecilochirus carabi, and Macrocheles
 nataliae that coexist on the same host-burying beetle Nicrophorus
 vespilloides and use it to ‘hitchhike’ between reproductive sites. Field
 observations revealed clear spatial partitioning between species in
 distinct host body parts. P. carabi preferred the ventral side of the
 thorax, whereas M. nataliae were exclusively found ventrally at the hairy
 base of the abdomen. Experimental manipulations of mite density showed
 that each species preferred these body parts, largely regardless of the
 density of the other mite species on the host beetle. Force measurements
 indicated that this spatial distribution is mediated by biomechanical
 adaptations, because each mite species required more force to be removed
 from their preferred location on the beetle. While P. carabi attached with
 large adhesive pads to the smooth thorax cuticle, M. nataliae gripped
 abdominal setae with their chelicerae. Our results show that specialist
 biomechanical adaptations for attachment can mediate spatial niche
 partitioning among species sharing the same host.
description: We explored the spatial niche partitioning between two phoretic
 mite, Poecilochirus carabi, and Macrocheles nataliae, that coexist on the
 host-burying beetle Nicrophorus vespilloides. We further provided evidence
 with biomechanic approaches to reveal the underlying adaptive values of
 attachment to beetle's cuticle surface. We first surveyed the natural
 densities of mites on field-collected beetles, and determined their
 preferred attachment sites on beetles. Next, we manipulated densities of
 both mites to investigate how intra- and inter-specific interactions
 influenced mite spatial distribution. Using electron microscopy, we
 quantified the cuticle surface of all beetle body parts and mite
 attachment devices. To further assess if mite preference for specific
 attachment sites is adaptive, we tested mite attachment to both beetle
 surface and artificial test substrates. Together, we showed that
 specialised mite attachment to different beetle's body parts mediate
 spatial niche partitioning among mite species on their carrier.
description: # This is the repository for data and codes used in mite biomechanics
 paper Biomechanical adaptations mediate spatial niche partitioning between
 phoretic mite species on burying beetles Syuan-Jyun Sun1,2,† ,*, Simon
 Chen1,†, Walter Federle1, and Rebecca M. Kilner1 1 Department of Zoology,
 University of Cambridge, Downing Street, Cambridge, CB2 3EJ, UK. 2
 International Degree Program in Climate Change and Sustainable
 Development, National Taiwan University, Taipei 10617, Taiwan †These
 authors contributed equally to this study. *Corresponding author:
 Syuan-Jyun Sun Email: We explored the spatial
 niche partitioning between two phoretic mite, Poecilochirus carabi and
 Macrocheles nataliae, that coexist on the host burying beetle Nicrophorus
 vespilloides. We further provided evidence with biomechanic approaches to
 reveal the underlying adaptive values of attachment to beetle's
 cuticle surface. We first surveyed the natural densities of mites on
 field-collected beetles, and determined their preferred attachment sites
 on beetles. Next, we manipulated densities of both mites to investigate
 how intra- and inter-specific interactions influenced mite spatial
 distribution. Using electron microscopy, we quantified the cuticle surface
 of all beetle body parts and mite attachment devices. To further assess if
 mite preference for specific attachment sites is adaptive, we tested mite
 attachment to both beetle surface and artificial test substrates.
 Together, we showed that specialised mite attachment to different
 beetle's body parts mediate spatial niche partitioning among mite
 species on their carrier. #### **Explanations for variables**: 
 **Fieldanalysis**: * Date: date of trapping event * year: year of trapping
 event * site: G (Gamlingay Wood)/W (Waresley Wood) * id: individual id *
 Trap: specific sites of trapping * body: beetle body parts * Sex: sex of
 beetles * bodysize: pronotum width of beetles * totalarea: total surface
 area of a given beetle (mm^2) * area: surface area of a given body part of
 a given beetle * head: surface area of the head of a given beetle *
 thorax: surface area of the thorax of a given beetle * abdomen: surface
 area of the abdomen of a given beetle * pronotum: surface area of the
 pronotum of a given beetle * elytra: surface area of the elytra of a given
 beetle * presence: presence of P. carabi only (big), M. nataliae only
 (small), both (both), or none (none) * bighead: number of P. carabi on the
 head of a given beetle * bigthorax: number of P. carabi on the thorax of a
 given beetle * bigabdomen: number of P. carabi on the abdomen of a given
 beetle * bigpronotum: number of P. carabi on the pronotum of a given
 beetle * bigelytra: number of P. carabi on the elytra of a given beetle *
 bignum: total number of P. carabi on a given beetle * predbighead:
 predicted number of P. carabi on the head of a given beetle, when
 multiplying the total number of mites by the percentage of each body part
 * predbigthorax: predicted number of P. carabi on the thorax of a given
 beetle, when multiplying the total number of mites by the percentage of
 each body part * predbigabdomen: predicted number of P. carabi on the
 abdomen of a given beetle, when multiplying the total number of mites by
 the percentage of each body part * predbigpronotum: predicted number of P.
 carabi on the pronotum of a given beetle, when multiplying the total
 number of mites by the percentage of each body part * predbigelytra:
 predicted number of P. carabi on the elytra of a given beetle, when
 multiplying the total number of mites by the percentage of each body part
 * newbigmiteintensity: density of P. carabi (local number divided by local
 surface area) on a given body part * oldbigintensity: total density of P.
 carabi (total number divided by total surface area) of a beetle *
 smallhead: number of M. nataliae on the head of a given beetle *
 smallthorax: number of M. nataliae on the thorax of a given beetle *
 smallabdomen: number of M. nataliae on the abdomen of a given beetle *
 smallpronotum: number of M. nataliae on the pronotum of a given beetle *
 smallelytra: number of M. nataliae on the elytra of a given beetle *
 smallnum: total number of M. nataliae on a given beetle *
 newsmallmiteintensity: density of M. nataliae (local number divided by
 local surface area) on a given body part * oldsmallintensity: total
 density of M. nataliae (total number divided by total surface area) of a
 beetle **force**: * miteid/id: individual id of mite * mite: species of
 mite * substrate: tested on substrate or on beetle * tr: specific body
 parts that mites were tested * angles: angles of pulling force * force:
 strength of pulling force (mN) **hair quantification on abdomen**: * id:
 beetle individual id * replicate: replicates of sampled area on a given
 beetle * num: number of hairs * type: type of hair (long/short)
 **labspacecompetition**: * id: beetle individual id * tr: mite density
 treatments (eg l50s50, meaning 50 P. carabi + 50 M. nataliae) * body:
 specific body parts * mite: mite species * num: number of mites *
 newintensity: the density of mites (for P. carabi or M. nataliae) on each
 specific body part * bodysize: pronotum width of a beetle * sex: sex of a
 beetle * bignum: number of P. carabi placed * bigintensity: the total
 density of P. carabi on a beetle * smallnum: number of M. nataliae placed
 * smallintensity: the total density of M. nataliae on a beetle *
 naturalsetting: mite density for natural setting comparison (1), i.e. P.
 carabi ranging from 1, 10, 50, whereas, M. nataliae ranging from 1, 3, 5.
 **longhairnum**: * imageid: image id of each beetle * id: individual
 beetle id * replicate: replicated sampling sites of each image * num:
 number of hair * body: beetle's body parts * hairlength: hair type as
 long or short * hairdensity: T for comparing long hair density on thorax
 vs short hair density on abdomen **mite reproduction**: * pair: pairing id
 * wt: carcass mass (g) * bl: block of experiment * male: specific family
 that the male originated * female: specific family that the female
 originated * mitetr: mite species * mitenum: number of mite offspring
 **padarea**: * videoid: video id * mite: mite species * miteid: id of
 individual mite * stepid: step id of each individual mite * area: pad
 contact area (um^2)