Impact of Land Reclamation on the Diversity of Darkling Beetles, (Tenebrionidae) in Arid Ecosystem of El-Kharga, New Valley Governorate, Egypt

Citation: Egypt. Acad. J. Biolog. Sci. (A. Entomology) Vol. 11(6)pp: 3749 (2018) Egyptian Academic Journal of Biological Sciences is the official English language journal of the Egyptian Society for Biological Sciences, Department of Entomology, Faculty of Sciences Ain Shams University. Entomology Journal publishes original research papers and reviews from any entomological discipline or from directly allied fields in ecology, behavioral biology, physiology, biochemistry, development, genetics, systematics, morphology, evolution, control of insects, arachnids, and general entomology. www.eajbs.eg.net Provided for non-commercial research and education use. Not for reproduction, distribution or commercial use.


INTRODUCTION
The ground dwelling invertebrates like beetles play significant roles in most terrestrial ecosystems.Beetles are highly diverse and occupy a wide range of microhabitats and consume different food resources (Borror et al., 1989;Höolldobler and Wilson, 1990).Among the beetles, Tenebrionids are relatively abundant, enormous, cursorily, readily captured in pitfall traps and the most simply identified (Henschel et al., 2010;Saji and Al Dhaheri, 2011;Abd El-Wakeil et al., 2014).The Tenebrionidae (darkling beetles) is a family of beetles with some 20,000 described species worldwide.They are extremely variable in shape, size and ecological requirements.
Beetles are one of the key components of arid environments, it is important to know how they are affected by changes in the spatial heterogeneity of vegetation.This knowledge lets us expect how human activities are probable to influence diversity and distribution of beetles and in the end their impacts on a variety of ecosystem processes (Lescano et al., 2017).In arid ecosystems, irregular distribution of plant communities acts as biotic cores (Liu et al., 2016), which have important significances on arid land dynamics (Liu et al., 2011).
Darkling beetles are a dominant group among the invertebrate fauna of arid environments (Cepeda-Pizarro et al., 2005;Carrara et al., 2011).Tenebrionids generally feed on the material of plant origin including decaying matter, wood, leaf litter, pollen, as well as fungal and algal matter.Some are also scavengers while very few species are predatory especially of wood-boring beetles.They involved in many ecological processes, such as predation, organic matter consumption, soil nutrient cycling, pollination, seed dispersal, plant anti-herbivore defense, and food for vertebrates (Andersen et al., 2004;Sackmann and Farji-Brener, 2006;Lach et al., 2010;Lescano, et al., 2017).
The New Valley Governorate is located in the southwestern part of Egypt; consisting of roughly a third of Egypt's area.It is the country's largest governorate and one of the biggest on the African continent.Compared with studies done on darkling beetles (Tenebrionidae) in Egypt, Many studied was concerned with Tenebrionidae in Egypt e.g.Fakhry (1994), Fadl et al. (1996), Ramadan (2001), Semida et al. (2001) Osman (2002), El-Gohary (2004), Abd El-Moez (2005), El-Wafeef (2007), El Metwally (2008) and Ramzy (2015), there was no study on the assemblages of Tenebrionid beetles in the New Valley Governorate.
Vegetation type, cover and plant community changes can affect, directly or indirectly, the abundance, species richness and composition of beetle communities (Stapp, 1997;Schweiger et al., 2005;Woodcock et al., 2010;Pakeman and Stockan, 2014).Impacts of land use/cover variations on biodiversity well documented in many parts of the world (Perner and Malt, 2003;Koellner and Geyer, 2013;Souza et al., 2015;Li et al., 2016).New Valley Governorate, Egypt, is facing a serious challenge of landscape change due to land reclamation.Therefore, the study aimed to assess the impact of land reclamation on the distribution, diversity and monthly occurrence of darkling beetles (Tenebrionidae) in El-Kharga, New Valley Governorates, Egypt.

Sites of Collection:
Four different reclaimed sites were selected in the experimental farm of New Vally University at El-Kharga, New Valley Governorate named site I, site II, site III and site IV (Fig. 1).They represented 4 different habitats; the site I is long-ago (more than 20 years) reclaimed land, site II is recently (10 to 20 years) reclaimed, the reclaimed age of site III is 5 years while site IV is not reclaimed yet.

Sampling:
Monthly quantitative samples were collected from the investigated sites during a period extended from September 2015 until February 2016.Pitfall traps were used for collecting samples.4 traps were used monthly at each site.Each trap was filled with 70 ml water and 5 drops of liquid soap and sheltered by plastic sheets to prevent falling of leaf litters in the traps.The traps were evenly distributed in the site.The aggregated beetles in the traps were collected every 10-12 days.The data were standardized by the equation of N/ (d*Tr) where N = number of beetles in one sample in the investigated site, d = number of days between two sampling and Tr = number of succeed traps (some traps were excluded and replaced by effective one) (Abd El-Wakeil, 2009, Ramzy, 2015).

Measurement of Ecological Factors:
The following environmental factors were monthly recorded during the period of investigation for each site of collection: temperature (air and surface soil), soil pH, relative humidity and wind velocity.

Statistical Analysis:
The collected data were summarized and analyzed using SPSS software (Version 21) and Microsoft Excel (2010).Analysis of variance (ANOVA) was applied to study the significant differences between sites and months for different collected beetles.In case of significant differences, Duncan's Multiple Rang Test (DMRT) was selected to detect the distinct variances between means.The program Canoco 4.5 for windows was used to perform canonical corresponded analysis (CCA) as a unimodal method to analyze the response of the collected species of beetles and corresponding investigated ecological factors.

RESULTS
The Recorded Environmental Factors: The temperature of air, soil temperature and wind velocity recorded highly amount in site VI (23.07±7.76,18.09±0.77and 5.72±1.18,respectively), soil pH was highest in the site I (6.59±0.40),while the relative humidity was higher in site II (45.61±9.92)(Table 1).There were no significant differences between environmental factors in the four sites.The investigated sites represented differences in the ground plants (Table 2).The Collected Coleoptera: The total number of beetles was 4725 individuals which belong to 7 species of beetles from one family, Tenebrionidae.The species were: Akis elevata Solier , Prionotheca coronata Olivier, Mesostena angustata Fabricius (= Mesostena elegans Solier; = Mesostena punctate Eschscholtz), Trachyderma hispida (Forskal) (= Tenebrio hispida Forskal; = Ocnera hispida latreillei Solier), Akis reflexa Fabricius , Pimelia arabica Klug and Scaurus puncticollis Solier .A. elevata, P. coronata were recorded in site I, M. angustata, T. hispida were recorded in site II, A. reflexa was recorded in site III, Pimelia Arabica was recorded in site IV and S. puncticollis was recorded in site III and IV (Table 3).There are highly significant differences of frequency among the collected species.The highest frequency was recorded by A. elevata (41.077).

Scaurus puncticollis
----------------0.71 ± 0.70a 0.35 ± 0.42b 12.467 <0.001 Akis reflexa ----------------0.54 ± 0.49 --------21.700<0.001 Composition and Abundance of The Collected: Table (4) shows the mean of densities (individual/day*trap) for the collected beetles at different study sites.The highest mean density was in the site I at September (6.25±2.18),while the lowest mean of individuals was in site IV at February (0.24±0.19).In site I, the mean of P. coronate and A. elevata were higher in number of individual/day*trap in September and October, the mean of M. angustata recorded the highest number of individual/day*trap at October and mean of T. hispida was higher at November in site II, the mean of S. puncticollis was higher number of individual/day*trap at October in site III than at site IV, the mean of A. reflexa recorded the highest number of individual/day*trap at September and November in site III and the mean of P. arabica was higher number of individual/day*trap at September in site IV (Fig. 2).

Statistical results:
Statistical test (ANOVA) was applied to show the significant differences between sites and months for different beetles species.Table (5) shows the results of this analysis, which can be summarized in the following points: There were significant differences in A.elevata at site I and S. puncticollis at site III.There were highly significant differences in P. coronata at site I and M. angustata at site II.Canonical Corresponding Analysis (CCA) for the beetles was illustrated in figures (3); it shows that: A. elevata and P. coronate were positively correlated with air temperature and negatively correlated with soil pH.
Mesostena angustata, T. hispida and P. arabica were positively correlated with soil temperature and wind velocity, while they were negatively correlated with relative humidity.
S. puncticollis and A, reflexa were positively correlated with relative humidity and negatively correlated with soil temperature and wind velocity.

DISCUSSION
The present results indicate that the abundance and diversity of the darkling beetles (Coleoptera: Tenebrionidae) are correlated with the site conditions.The relatively low abundance of tenebrionids (seven species) in the investigated study area may be due to the agricultural activities of this area.Aldryhim et al. (1992) found that cultivated area has lower tenebrionids abundance than uncultivated one.Li et al. (2016) noted that the beetle community is largely determined by plant cover and diversity.Similar results were observed during the current study whereas the beetle abundance and density were impacted by plant diversity.Relatively high plant diversity increase beetle densities.Plant groves may be the reason for the relatively low diversity of tenebrionid beetles in the investigated sites.Li et al. (2016) concluded that shrub plantations reduce beetle diversity.Many research illustrated that the main cause of reducing the biodiversity of many terrestrial ecosystem is the changes in the land use/ cover (Garnier et al., 2006;Krauss et al., 2010;Garcia-Tejero et al., 2013;Vergnes et al., 2014;Sweaney et al., 2015).Liu et al. (2015) concluded that shrub diversity and season variations are the significant factors for ground beetle assemblages in the desert ecosystem, while the responses of beetles varied among trophic and taxonomic levels.
Beetles are adept of existing in a wide range of arid environments (Marcuzzi 2005;Saji and Al Dhaheri, 2014).The thick sclerotization of body integument of adult tenebrionids helps them to be highly tolerating dry and hot conditions (Aldryhim et al., 1992;Piňero and Gómez, 1995;Saji and Al Dhaheri, 2011).They are able to survive under harsh environmental conditions as a result of physiological and behavioral adaptations (Cloudsley-Thompson, 2001;Carrara et al., 2011).Abd El-Wakeil et al. (2014) illustrated that Tenebrionidae escapes from tough climate by burying themselves underground to avoid the sand's very high temperatures emerging periodically each day (Seely et al., 1988).Many of them cover their exoskeleton by wax, which reflecting some of the sun's heat and protecting them from water loss (Chown and Nicolson, 2004).
Interaction of many environmental factors may control the variations in biodiversity; species composition, evenness and diversity indices, which include microclimate favorites, resource availability, habitat quality, grazing or the disturbance itself (Hardersen et al., 2014;Aldhafer et al., 2016).The present results indicated that species diversity of tenebrionids varied among the different investigated sites.Semida et al. (2001) illustrated that species diversity not only varied among the different localities but also, sometimes within localities.These differences may relate to the heterogeneous of habitat conditions which affect the spatial and temporal existence of beetles (Wiens 1976, Addicott et al., 1987;Niemelä et al., 1992;Yu et al., 2016).Ohwaki et al. (2015) mentioned that heterogeneity is a key feature determining biodiversity in agricultural landscapes (Weibull et al., 2000;Kato, 2001;Benton et al., 2003).
Several studies illustrated that seasonal fluctuation is a feature of most ecosystems, particularly in deserts, where the temperature and rainfall fluctuations affect animal productivity and activity (Ayal and Merkl, 1994;Blondel and Aronson, 1999;Miranda, 2007;Sackmann and Flores, 2009;Abd El-Wakeil et al., 2014;Liu et al., 2015;Bartholomew and El Moghrabi, 2018).Monthly variation of the recorded tenebrionid density was proved in the current study.Generally, higher densities of tenebrionids were recorded during September and October.Bartholomew and El Moghrabi (2018) recorded similar results for tenebrionids which inhabiting Sharjah, United Arab Emirates.They recorded significantly higher beetle activity levels during the late autumn.They suggest that tenebrionid beetles prefer shrubs during hotter seasons of the year, because shrubs shelter them from extreme temperatures, not because of reduced predation risk or greater food availability.Liu et al. (2015) suggested that in autumn the food resources attracted beetle due to the decrease in solar radiation stress and soil temperature.Hawkins et al. (2003) found a strong positive correlation between water availability and richness of a wide range of animal groups in water-limited environments.In contrasts with this the present results show negative correlation between the abundance of the collected M. angustata, O. hispida and P. arabica species with relative humidity.This is agreeing with the results recorded by Carrara et al. (2011).They illustrated that tenebrionid richness is significantly negatively related to water availability.The reasonable explanation of this negative relationship is that the organisms occupying a harsh environment with high energy and water availability may decrease their resource consumption rates to avoid water loss.Therefore, the relative strength of the conflicting effects of water and energy may effect on animal abundance (Mueller and Diamond, 2001;Williams and Tieleman, 2002;Carrara et al., 2011). De Los Santos et al. (2002) showed that the beetles have the capacity to regulate haemolymph osmolarity, and reduced respiration rates for conflict to desiccation and adaptation to arid environments (Gehrken and Sømme, 1994).Soil moisture appears to be a limiting factor for the presence of tenebrionids (De Los Santos et al., 2002;El Surtasi et al., 2012).
Among the collected species, Scaurus puncticollis was the only species recorded in two sites (sites III and IV).Previous studies indicated that species of the genus Scaurus can inhabit a large variety of habitats (Mas-Peinado et al., 2013).This species has a wide geographic range (Löbl, et al., 2008).The abundance of P. coronata recorded the highest value (1.85±1.66individual/day*trap) among the other seven collected species and it observed during the entire period of the study with peaks in September and October.Saji and Al Dhaheri (2011) documented that P. coronata is one of the most abundant species as the most dominant in the terms of its density and monthly occurrence in the Western region of Abu Dhabi, UAE.They recorded that the highest number of this species was between October and November.The high density of this species may relate to the high rate of its mobility.
In conclusion, this work is the first to describe tenebrionid beetle assemblages in El-Kharga, New Valley Governorate, Egypt.The results indicated that the environmental fluctuations and human activities that affect vegetation structure would lead to variations in the community of tenebrionid beetles affecting the variety of ecosystem in which they are intricate.This highlights the significance of considering human activities of land reclamation for developing management policies to conserve biological diversity in arid ecosystems.The present information is vital for any future monitoring fluctuations in beetle communities and their role in biological cores within arid ecosystems.

Fig. 2 .
Fig. 2. Monthly variations for the mean density (individual/day*trap) of collected beetles at the studied sites during the period of investigation.(The similar characters for each species show no significant difference).

Table 1 .
Mean ± standard deviation (SD) of investigated ecological factors at the study sites during the period of investigation and the statistical results.

Table 3 .
The mean values of densities (individual/day*trap) of collected beetles from the study sites during the period of investigation

Table 4 .
The mean values ±standard deviation (SD) of densities(individual/day*trap) for the collected beetles at different study sites during the period of investigation.

Table 5 .
ANOVA results for differences between monthly densities of collected beetle species at different study sites during the period of investigation