To assess the effects of seasonality on alpine dung beetle assemblages, data were collected from a site in the Troncea valley (termed the Troncea B site) in the western Italian Alps over four occasions in 2011.

Historically, surveys specifically focused on dung beetles in the western Italian Alps have occurred a total of thirteen occasions, spread unevenly across eleven valleys (the Argentera, Chalamy, Champorcher, Ferret, Gressoney, Grande, Lourousa, Sessera, Troncea, Valletta and Veny valleys) and the years 2005 to 2012 (Chamberlain et al. 2015, Tocco et al. 2013a, Tocco et al. 2013b, Negro et al. 2011a, Negro et al. 2011b, Macagno and Palestrini 2009, Palestrini et al. 2008a, Palestrini et al. 2008b) (Fig. 1). The location and climatic characteristics of the valleys are summarised in (Table 1).

Figure 1.  

Illustration of the eleven valleys in the western Italian Alps where dung beetle surveys were carried out.

Seasonal sampling at Troncea B was carried out using pitfall traps with bait suspended over them using a tripod (Tocco et al. 2013a, Tocco et al. 2013b,Tocco et al. 2016). Each trap consisted of a 1.5 l clear plastic bottle, 9 cm in diameter, cut horizontally about 25 cm from its bottom: the top was cut and inverted to make a funnel that was inserted into the main 25 cm container. The bait, 200 g of fresh cow dung, was wrapped in gauze and suspended over the trap just above the funnel using a tripod made with three 50 cm-long sticks. A standard mixture of water, liquid soap (to reduce surface tension) and sodium chloride was used as a preserving fluid (Tocco et al. 2013a, Tocco et al. 2013b, Tocco et al. 2016). Trapped beetles were preserved, taken to the laboratory, dried, counted and identified to species level using dichotomous keys (Dellacasa and Dellacasa 2006, Paulian and Baraud 1982). Examination of aedeagus was necessary in the case of groups containing cryptic species (Dellacasa and Dellacasa 2006).

Four early published surveys carried out in the Chalamy, Champorcher, Ferret and Veny valleys in 2005-2006 used active manual collecting of dung beetles from dung pads (Table 2). Ten later surveys in the Argentera, Chalamy, Ferret, Gressoney, Grande, Lourousa, Sessera, Troncea, Valletta and Veny valleys used pitfall traps baited with cow dung. The sampling effort (numbers of sampling sites, traps and events) reported in the original publications of each survey is collated in (Table 2). The surveys were all carried out in summer (June to September), corresponding to the activity period of adult Alpine dung beetles, on 1-19 occasions within a year, over one or two years, depending on the particular survey. Because the surveys used different survey methods, their abundance data were not strictly comparable and their results were therefore transformed to binary data (presence-or-absence records) with measures of sampling effort and collated into a single dataset.

Argentera valley (Piemonte, Italy): larch forest (Larix decidua Miller), shrub (Rhododendron ferrugineum L), alpine meadow (graminaceous plant) and grassland (graminaceous plant). Elevations ranged from 2203 to 2500 m a.s.l. Chalamy valley (Valle d’Aosta, Italy): beech forest (Fagus sylvatica L.), Scots pine forest (Pinus sylvestris L.), mountain pine forest (Pinus uncinata Mill.) and pasture (graminaceous plant). Elevations ranged from 1002 to 1997 m a.s.l. Champorcher valley (Valle d’Aosta, Italy): pasture (graminaceous plant). Elevation ranged from 1645 to 2584 m a.s.l. Ferret valley (Valle d’Aosta, Italy): Coniferous forests (dominated by larch, Larix decidua), wet meadows, shrub (Rhododendron ferrugineum L. and Vaccinium myrtillus L.), and anthropogenic woods for picnickers and pasture. Elevation ranged from 1500 to 2062 m a.s.l. Grande valley (Piemonte, Italy): forest, shrub, alpine meadow, and grassland. Elevation ranged from 1753 to 2180 m a.s.l. Gressoney valley (Valle d’Aosta, Italy): larch forest, shrub (Juniperus nana Willd), alpine meadow, and grassland. Elevation ranged from 1959 to 2772 m a.s.l. Lourousa and Valletta valleys (Piemonte, Italy): pasture dominated by Festuca gr. ovina, Festuca scabriculmis, and Rumex alpinus. Elevation of Lourosa and Valletta sampling site was 1959 and 1743 m a.s.l., respectively. Sessera valley (Piemonte, Italy): beech forest, pioneer forest (Picea abies L.), shrub (Rhododendron ferrugineum L) and pasture. Elevation ranged from 1000 to 1600 m a.s.l. Troncea valley (Piemonte, Italy): shrub (Rhododendron ferrugineum L and Juniperus nana Willd). Elevations ranged from 1960 to 2360 m a.s.l. Veny valley (Valle d’Aosta, Italy): pasture. Elevation ranged from 1550 to 2200 m a.s.l.

Coordinates

Argentera valley: 44°54'N; 6°54'E. Chalamy valley: 45°41'N; 7°38'E. Champorcher valley: 45°36'N; 7°34'E. Ferret valley: 45°50'N; 7°01'E. Gressoney valley: 45°51'N; 7°48'E. Grande valley: 45°22'N; 7°16'E. Lourousa valley: 44°12'N; 7°16'E. Sessera valley: 45°40'N; 8°05´E. Troncea valley: 44° 57’N, 6°. 57’E. Valletta valley: 44°10'N; 7°16'E. Veny valley: 45°46'N; 6°52'E.

; .

The published surveys collectively report 46 species of dung beetle inhabiting eleven valleys of the western Italian Alps, surveyed irregularly over seven years Table 3. The communities in all valleys were dominated by Aphodiinae Leach, 1815, both by abundance and by species richness. Geotrupidae Latreille, 1802 and Scarabaeidae Latreille, 1802 form a smaller part of the communities, the proportion depending on the valley. Our nomenclature follows Dellacasa and Dellacasa (2016). In the table we listed Onthophagus vacca Linnaeus recorded by Macagno and Palestrini (2009) from Chalamy valley, but this record my pertain to Onthophagus medius (Kugelann) (see Rössner et al. 2010).

The Troncea B survey collected a total of 22 dung beetle species belonging to the Scarabaeidae (Aphodiinae and Scarabaeinae) and Geotrupidae (Suppl. material 1). Voucher material is deposited in the Department of Life Sciences and System Biology, University of Torino, Italy.

These data can be freely used, provided their source is cited.