Distributional Patterns of Carabid Beetles under Humid Subtropical Climate in Croplands of Sialkot

Pakistan with its diverse climatic and topographical features, is expected to harbor a great diversity of insect species; however, insect fauna of global significance lacks taxonomic and ecological exploration in Pakistan. We explored species diversity and community composition of carabid beetles from croplands. Sampling was conducted fortnightly from August 2020 to July 2021 from district Sialkot i.e., Sialkot, Sambrial, and Pasrur. Specimens were collected by handpicking during the day while pitfall traps were used for nocturnal sampling. Diversity indices and similarities percentage (SIMPER) were calculated for all study sites. We reported 15 species belonging to four subfamilies, six tribes, and eight genera. Calosoma inquisitor (15.18%), Pheropsophus verticalis (12.37%), and Pheropsophus darwini (11.54%) were the most abundant species in district Sialkot. The values of diversity indices calculated for different sites show high species diversity and evenness in Sambrial (D = 0.09, e ˄ H/S = 0.94) followed by Pasrur (D = 0.08, e ˄ H/S = 0.93) and Sialkot (D = 0.11, e ˄ H/S = 0.84). Species richness was highest in Pasrur (H = 2.49) followed by Sambrial (H = 2.42) and Sialkot (H = 2.22). Galerita bicolor and Galerita lecontei veracrucis were reported as new to Pakistan. The study emphasized that ground beetles are one of the key components of agroecosystems and need to be explored extensively concerning accelerated habitat modification and habitat types.


INTRODUCTION
O ne of the key global issues is biodiversity loss in response to climate change, land-use practices, pollution, overexploitation, and agricultural intensification resulting in habitat modification, fragmentation, microclimatic variation, and habitat loss (Cardoso et al., 2020;Rounsevell et al., 2018;van der Meer et al., 2020).Climate change and extensive agriculture are key drivers of the global decrease in insect biodiversity (Raven and Wagner, 2021).The rate of species extinction is 1000 times faster compared to the historical trends, mainly due to climate change and associated anethropogenic activities (JM et al., 2015).To mitigate biodiversity decline, the conservation, and re-establishment of semi-natural habitats and less intensively managed habitats in agricultural landscapes have been encouraged (Wang et al., 2021).Several studies have identified agricultural practices and extension as principal contributing factors to species extinction (Wepprich et al., 2019;Forister et al., 2016;Raven and Wagner, 2021).

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wide distribution, and role as biocontrol agents of pests (Manzoor et al., 2020;Perveen, 2015;Bashir et al., 2023).Ground beetles (Carabidae) are abundant and speciesrich in cultivable areas across the globe with almost 40,000 species (Lövei and Sunderland, 1996).Carabid beetles exhibit various morphological forms and diverse ecological roles i.e., predation, herbivory, and scavenging (Lövei and Sunderland, 1996).Carabid species are sensitive to anthropogenic changes in soil habitats.Thus, they act as bioindicators and are used to characterize habitat disturbance by responding to changes in vegetation height, and supplementary habitats (corridors) for generalist and mesophilous species (Lövei and Sunderland, 1996;Rainio and Niemelä, 2003;Rebrina et al., 2022).Moreover, they are important pest-control agents due to their predatory polyphagous diet (Symondson et al., 2002;Vichitbandha and Wise, 2002).Carabid communities may serve as an important bio-indicators as well biocontrol agents in agricultural landscapes (Avgın and Luff, 2010;Skłodowski, 2017;Schwerk et al., 2020;Soomro et al., 2021).
Keeping in view the global importance of carabid beetles, we explored the diversity of carabid beetles from Sialkot.The objective of the study is to document the carabid beetles from farmland and seminatural habitats from Sialkot, Punjab, Pakistan.The study would help to assess diversity and the pattern of ground beetles' distribution in croplands of Sialkot.

Study area
Sialkot (32.3811°N, 74.4995° E) is one of the main districts of the province of Punjab, Pakistan.It is located in the northeast part of the province and is surrounded by Jammu Kashmir on the north, Narowal on the south, Gujranwala on the west, and Gujrat on the northwest side (Noreen et al., 2020).It covers an area of 1200 square miles and is 256m above sea level.Besides the Chenab River on the north side of Sialkot, three seasonal streams also flow through the city i.e., Palkhu, Aik, and Beer.The weather of Sialkot is extremely cold during winters while hot and humid during summer.Sialkot is the sub-humid, warm, and sub-tropical monsoon region of Pakistan (Khan, 2019).Winter temperature might fall to −2 °C and the average rainfall of district Sialkot is almost 1000 mm the highest rainfall is observed from July to September (District Sialkot, 2023).

Sampling procedure
Sampling was carried out fortnightly from randomly selected 15 sites within three tehsils i.e., Pasrur, Sambrial and Sialkot (Fig. 1).Sites were selected based on the vegetation type i.e., croplands and semi-natural habitats.Specimens were collected by handpicking from agricultural fields and seminatural habitats.Pitfall traps were also placed for nocturnal sampling in both type of habitats (Ullah et al., 2017).We used disposable plastic cups to prepare the traps with dimensions: diameter (52mm), top diameter (81mm), and height (110 mm).One-third bottom of the trap was filled with vinegar to kill and preserve the specimen.Traps were placed in a 1km transects.Transects were separated by ~100 m.A total of nine traps were placed at each sampling site which were separated by

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~150m.The open mouthed traps were surveyed after 24 h and the captured specimens were collected and transferred in labelled plastic containers.For the the reuse of already installed traps, the killing agent was drained and the traps were refilled (Mishkatullah, 2018).

Statistical analysis
The simpson and shannon-weiner diversity indices were applied using PAST3 statistical software to calculate species abundance, richness, and evenness across the study area.The similarities percentage (SIMPER) notes the species contributing to dissimilarity among different sites (Simpson, 1949;Shannon, 1949;Clarke and Gorley, 2015;Clarke, 1993;Clarke and Warwick, 1994).Seasonal relative abundance was calculated by arranging data seasonally, i.e. summer (April-October) and winter (November-March) (Hussain et al., 2022a).

Overall diversity and abundance
The results indicated that a total of 4558 ground beetle specimens were collected from Sialkot, Pasrur and Sambrial tehsils of district Sialkot from August 2020 to July 2021.The specimens belonged to four subfamilies, six tribes, eight genera, and fifteen species.The maximum number of species was recorded from genus Pheropsophus (7 species) followed by genus Galerita (2 species, Table I).

Diversity indices
The values of species dominanace (1-D) showed variations in the the diversity of species at a given site (value closer to 0 indicates less diversity while 1 indicates high diversity (Table II).The Simpson's index (1-D) shows that species are more diverse in Pasrur (1-D = 0.91) followed by Sambrial (1-D = 0.90) and Sialkot (1-D = 0.88).Similarly, Shannon index (H) indicate high species richness in Pasrur (H = 2.49) followed by Sambrial (H = 2.42) and Sialkot (H = 2.2).The evenness value (e ˄ H/S) indicated closer to 1 showed high evenness while a 0 value shows low evenness i.e., Sambrial (e ˄ H/S = 0.94) followed by Pasrur (e ˄ H/S = 0.93) and Sialkot (e ˄ H/S = 0.84).The equitability value (J) indicated that the species are almost equally distributed in Sambrial (J = 0.975) and Pasrur (J = 0.972) whereas in Sialkot (J = 0.927), species are less equally distributed as compared to Sambrial and Pasrur (Table II).Margalef index explains the impact of sample size on the soecies richness i.e., the higher the index the greater the richness.Pasrur (1.615) exhibited higher richness as compared to sambrial (1.506) and Sialkot (1.383).Species contributing to dissimilarity among different sites SIMPER results for the species contributing to dissimilarity among different sites in district Sialkot.Overall dissimilarity among Sialkot and Sambrial is 25.16%.Top species contributing to dissimilarity include Chlaenius pictus (18.33%),Scarites subterraneus (18%), and Pheropsophus verticalis (16.97%) whereas Pheropsophus hilaris sobrinus (0.11%) has the least contribution to dissimilarity among the species.Sialkot and Pasrur showed 16.06% dissimilarity in species distribution.Chlaenius pictus (28.78%) and Pheropsophus verticalis (22.62%) have the highest contribution to dissimilarity whereas, Poecilus versicolor and Galerita lecontei veracrucis have no contribution to dissimilarity (Table IV).

Rank abundance curve
Rank abundance curve reflects evenness in the slope of the line.Whereas a steep gradient represents low evenness, while a shallow gradient is indicative of higher species evenness.The rank abundance graph of species in three study sites showed a shallow gradient of Pasrur and Sambrial which indicated evenness in the distribution of species whereas the steep curve of Sialkot indicates low evenness in species abundance (Fig. 3).Pasrur and Sambrial were equally dominant sites as compared tehsil Sialkot.Dominant species included Pheropsophus africanus, Galerita lecontei veracrucis, Cymindis platicollis, Dioryche subrecta and Pheropsophus lissoderus (Table III).Fig. 3. Rank abundance graph of species in three tehsils (Sialkot, Sambrial, and Pasrur).

DISCUSSION
Ground beetles (family Carabidae) belong to a large family of predatory ground-dwelling beetles.The studies on carabid beetles report their dependence on biotic and abiotic features of their local habitats (Pizzolotto et al., 2018;Heino et al., 2019).Carabid community rely on vegetation characteristics mainly through local effects (Schaffers et al., 2008;Worthen and Merriman, 2013).Microclimatic conditions like food sources, temperature, moisture and sunlight influence carabid assemblages (Luff, 1980;Ernsting and Isaaks, 2000).In our study, we recorded 15 species of carabid beetles that belonged to the carnivorous guild from agricultural landscapes.Our study sites represent similarities in microclimatic conditions (temperature, light, and biotic communities), however local differences in vegetation and other features in three tehsils (Sialkot, Pasrur and Sambrial) were observed which have influenced species richness and abundance.
Ground beetle assemblages have been reported amongst important insect communities from the agricultural landscapes across the globe (Szyszko-Podgórska et al., 2021;Rainio and Niemelä, 2003).Interestingly, most species of carabids were observed with reasonably higher magnitudes from all three study sites except Scarites subterraneus (from Sambrial), Pheropsophus darwini (from Pasrur), Cymindis platicollis (from Sambrial) and Dioryche subrecta (from Sambrial).Poecilus versicolor was not recorded from Sialkot and Pasrur.Calosoma inquisitor, Chlaenius pictus, Pheropsophus verticalis and Poecilus versicolor (also from Pasrur) were not recorded from Sialkot.Additionally, these results of ground beetle assemblages recorded from district Sialkot indicated slight variations in the species abundance, richness, and distribution across the sites i.e., Sialkot, Sambrial, and Pasrur.

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Distributional Patterns of Carabid Beetles of Sialkot
Twelve species were reported from coastal areas of Sindh with most abundant species include Calosoma aurapunctuatum, Calosoma scyophantum and Anthia sexuamatta.The species belonging to the genus Pheropsophus were found to be the most abundant in Sialkot.Species were found to be evenly distributed in Sambrial and Pasrur (less anthropogenic activities) as compared to Sialkot (more anthropogenic activities).Similar results have been reported for changes in the composition and abundance of carabid species due to the disturbance caused by anthropogenic activities (Rainio and Niemelä, 2003).Habitat fragmentation, vegetation, and soil water content are the major factors affecting the distribution and abundance of carabid beetles (Wei et al., 2020;Kazi et al., 2016).The values of diversity indices show high species diversity and evenness in Sambrial followed by Pasrur and Sialkot.Species richness was highest in Pasrur followed by Sambrial and Sialkot.The seasonal diversity of carabid beetles has also been reported similar to our findings from Sindh, Pakistan (Sahito et al., 2020).

CONCLUSION
Carabid beetle assemblages indicated dominance of predatory species in croplands of Sialkot.Among 15 species recorded, Galerita bicolor and Galerita lecontei veracrucis were reported as new to Pakistan.Our study described Pheropsophus as the most abundant genus with seven species out of total fifteen species belong to this genus.Variations in the number of species from three tehsils indicated local differences in the microclimatic conditions in the sites.

Table IV . SIMPER results including species contributing to dissimilarities among sites.
O n l i n e F i r s t A r t i c l eS.Liaqat et al.