The influence of Formica exsecta ants on the abundance and diversity of other invertebrates in a private fragment of Tanzanias coastal forests

J. Bio. & Env. Sci. 20 23 1 | Mohamed RE RERE RESEARCH SEARCHSEARCH SEARCH PAPER PAPERPAPER PAPER OPEN ACCESS OPEN ACCESSOPEN ACCESS OPEN ACCESS The influence of Formica exsecta ants on the abundance and diversity of other invertebrates in a private fragment of Tanzanias coastal forests Nuru Said Mohamed * Department of Biology, Faculty of Science, Muslim University of Morogoro, Morogoro, Tanzania Article published on September 03, 2023 Key words: Formica exsecta , Invertebrates abundance and Diversity, Tanzania’s Coastal Forests Abstract This study was conducted in the fragment of Tanzania’s Coastal Forests (TCFs), which is one of the world’s ecoregions with varied endemic flora and fauna located on the coast of Indian Ocean. Its focus was on privately-owned TCFs, specifically a research and conservation centre of the late Prof. R.B.M Senzota since 1988. This fragment faces pressure from the surrounding population of more than seven million people of the Dar es salaam city, causing two visible habitat disturbances (disturbed and less disturbed) coupled with the outbreak of invasive species. The study assessed the influence of invasive Formica exsecta in varied disturbance levels and dry and wet seasons to invertebrate abundance and diversity. Pitfall trap, baited trap and dry leaf litter sifting were used in the invertebrate collection. The result show that this TCFs fragment to have higher invertebrate biodiversity with 484,481 individuals, 134 species, 87 families and 18 orders. Contrary to many findings, the disturbed habitat and dry season had higher abundance with lower diversity and species number compared to the less disturbed habitat and wet season with lower abundance but higher diversity and species number. Over dominance of aggressive Formica exsecta in the disturbed habitat and dry season by more than 90 present of all the individuals collected highly contributed to this variation as was also negative correlated to invertebrate abundances (r = -0.0012). The threat of the TCFs endangers enormous endemic wildlife; hence the need for the ultimate conservation efforts integrating both private and public-owned small and larger fragments before it was too late. * Corresponding Author: Nuru Said Mohamed  nurumoha[email protected]c.tz Journal of Biodiversity and Environmental Sciences (JBES) ISSN: 2220-6663 (Print) 2222-3045 (Online) Vol. 23, No. 3, p. 1-12, 2023 http://www.innspub.net J. Bio. & Env. Sci. 20 23 2 | Mohamed Introduction Tanzania’s Coastal Forests (TCFs) refer to an ecological region globally recognised as biodiversity hotspots with varied endemic flora and fauna located along the Indian ocean coast in five regions of Tanzania Mainland (Tanga, Pwani [Coast], Dar es salaam, Lindi, and Mtwara) and Zanzibar Islands (Unguja and Pemba) (Burgess, 1992; Burgess, 2018). Out of the five TCFs regions on Tanzania Mainland, Dar es Salaam had the least protected forest reserve (Burgess, 2018) partly because of the over-crowding of the region with more than seven million people as reported by the World Population Review (WPR) (2023). Such population pressure exerted on the mosaic of forests require recourse to a variety of ecological and economical services for sustaining ecological cycles, controlling floods and soil erosion control, and support for carbon sequestration, medicinal plants, fuelwood and charcoal production, food sources and building materials (Senkoro, 2015; Wilson, 2011). Despite these significances, TCFs face rapid degradation largely due to uncontrolled fires, indiscriminate clearing of vegetation for settlement, agriculture, logging and charcoal making (Burgess, 1992; Mohamed, 2016). Consequently, there is an urgent to protect the numerous private-owned small fragments and a few large fragments owned by the government as national parks and forest reserves such as Saadani National Park, Pugu and Kazimzumbwi Forest Reserves, Kiwengwa-Pongwe, and Masingini catchment forest on Unguja, and Misitu Mkuu and Ras Kiuyu on Pemba. Most of the conservation efforts focus on government forest reserves, ignoring the small patches despite being home to relatively higher in biodiversity (Braschler et al., 2020). The former Dar es salaam Bioenvironmental Centre (DBC) is one of the private-owned small fragments of the TCFs highly affected by the continual wanton forest deforestation. Based on floral structures and density, Senkoro (2015) divided the DBC into two visible levels of habitat disturbance: The disturbed habitat and the less disturbed habitat. The present study used these two discernible levels of habitat disturbance to assess the effects of habitat disturbance on invertebrate abundance and diversity. Indubitably, TCFs are known for their high diversity in invertebrate fauna (Mohamed, 2016) such as ground beetles, ants, and pollinator insects such as butterflies. Invertebrates are well known for their varied ecological roles despite attracting less attention in the world of science with the exception of insect pollinators. Invertebrates are ecologically known as ecosystem engineers, bio-indicators, and predators for a variety of pests (Cerdá & Dejean, 2011; MoraRubio & Parejo-Pulido, 2021; Kotze et al., 2022). The ongoing environmental disturbances in TCFs have occasioned many effects on the ecosystems, including the invasion of non-native species such as Formica exsecta originally found in European alpine regions and Asia (Sundström & Vitikainen, 2022). Formica exsecta, as one of the social insect species, may have many negative effects on other invertebrates including high competition for the food resources and habitat available as found by (Lenoir, 2001) to be a key-stone predator on soil fauna, similar to its close relative Formica (Coptoformica) pressilabris (Hakala et al., 2020). The present study, thus, assessed their influence on invertebrate diversity in the two forest disturbance levels of the TCFs fragment. Since studies have attested to how invertebrate biodiversity is highly affected by seasonal differences (Owens et al., 2022), the present study also evaluated the contribution of the two distinct wet and dry seasons evidently in the Dar es Salaam city (Ndetto & Matzarakis, 2013; Weather Spark, 2023) in May and November, respectively, to invertebrate abundance and diversity for the two levels of habitat disturbance in the TCFs fragment under review. Materials and methods The study was conducted between November, 2014 and May, 2015 in the Tanzania’s Coastal Forests (TCFs) generally and specifically a fragment formerly known as the Dar es salaam Bioenvironmental Centre (DBC). This area is located along the south-west coast of Indian Ocean, Kilimahewa, Kinondoni, Dar es Salaam, Tanzania (at 6 0 41’20.33” S 39 0 11’10.60” E, Fig. 1). The DBC was a seven-hectare TCFs fragment on an elevation of more than 90m asl, with a stable tropical climatic condition sustained by the Indian J. Bio. & Env. Sci. 20 23 3 | Mohamed Ocean breeze. This TCFs fragment served as a research and conservation centre under the ownership of the late Prof. R. B. M. Senzota since 1988 (Mohamed, 2023). The fragment had come under rising pressure from more than seven million human population of Dar es Salaam City due to several urbanisation activities such as waste disposals, burning and clearance of vegetation cover for settlement and many other uses to suffice its population. Fig. 1. Map of Dar es Salaam showing location of the study site (●), the Tanzania’s Coastal Forests Fragment (modified from Mohamed, 2023). The present study used pitfall traps, baited traps, and dry leaf litter sifting methods to collect invertebrates in the field. The study spent 18 days, each month from November 2014 up to May 2015 when nine days were available on collecting specimen for investigation. Pitfall traps and baited traps had seven successive days whereas dry leaf litter sifting method accounted for two days after every other day to minimise the disturbance effects around the study site. The specimens collected were conveyed to the laboratory for sorting out and identification purposes with invertebrate experts from the University of Dar es Salaam. Various field guides and other identification books were also used which includes McGavin (1992), McGavin (1993), Picker et al., (2004), Scholtz & Holm (1996), and White (1983). Pitfall trapping Pitfall trapping has emerged to be the most efficient method for sampling invertebrates such as beetles, ants, millipedes and earthworms (Shayya & Lackner, 2020; Cajaiba et al., 2017; Samways et al., 2010). It has also known to be simple and less expensive and can sample species missed by other trapping methods (Niba & Yekwayo, 2016; Nyundo & Yarro, 2007). Thus, the present study decided to adopt pitfall trapping method in sampling invertebrates’ fauna despite its complications during data interpretation. During specimen collection, 50 pitfall traps were buried fresh with the ground surface in two transects. Each transect comprised 25 pitfall traps (5 metres from one another) giving 100-metre long. Plastic container of one-litre volume with diameter of 8cm at the base, 12cm at the mouth and 14.8cm in height was used to create these pitfall traps. The buried pitfall traps were half-filled with soapy water and each trap was emptied in a nylon bag with 75 present ethanol three times a day early in the morning (from 9.00am), during afternoon (from 2.00pm) and in the evening (from 6.00pm). This setup was applicable in each of the dry and wet seasons and thus making a total of 100 pitfall traps in the whole study. Dry leaf litter sifting method On the other hand, the Dry leaf litter sifting method has been appreciated in the world of science as one of the best and most successful method for collecting invertebrate individuals such as ants and ground dwelling beetles (Shayya & Lackner, 2020; Wiezik et al., 2015; Jacobs et al., 2011; Samways et al., 2010). In this regard, the present study opted for the dry leaf litter sifting method to collect invertebrate animals in both seasons and data on levels of habitat disturbance. A total of five quadrats of 1m x 1m size each were randomly sampled in each of the disturbed and less disturbed habitats in a distance of not less than 15 metres, hence 10 quadrats in each of the dry and wet seasons. The sampling was made in the morning hours (from 9.00am to 11.00 am) during which the J. Bio. & Env. Sci. 20 23 4 | Mohamed dry leaf litter and debris collected were emptied onto a piece of white cloth and invertebrate faunas were separately retrieved by hand, forceps, and aspirator into a nylon bag half filled with 75 present ethanol and taken in to the laboratory for identification. Baited trapping Invertebrate faunas continued being attracted to many baits such as sugar and honey (Mohamed, 2023), whose effectiveness in attracting numerous invertebrate individuals has already been determined (see, for example, Yousefi et al., 2020; Crane & Baker, 2011; Müller & Schlein, 2011). Ten (10) mills of each of the two solutions comprised brown sugar from Kilombero Sugar Company and Tan HONEY harvested from Tabora region in Tanzania (the baits) were separately poured into a bottle of 500 mils with mouth diameter of 2.2cm and left open on the ground where invertebrates entered to follow the bait. The entered specimens were collected three times a day, early in the morning (from 9.00 am), during afternoon (from 2.00pm) and in the evening (from 6.00 pm) from which they were emptied into nylon bags half filled with 75 percent of ethanol and conveyed to the laboratory for identification. The sugar baited solution was made with 1kg of sugar dissolved in 3 litres of water whereas the honey baited solution was used directly as derived from Tan HONEY sourced from Tabora region. Each of the sugar and honey baited solutions had four transects (two in each of the dry and wet seasons) with 100 metres long and 100 baited bottle traps (50 apiece for the two seasons) with a distance of 5 metres between traps. Out of the two transects for each of the dry and wet seasons, the disturbed and less disturbed habitat had one transect each. Also, out of the 50 baited bottle traps for each of the dry and wet seasons for both the disturbed and less disturbed habitats. This setup resulted in eight transects and 200 baited bottle traps for the study. The abundance of the invertebrate individuals collected between the two disturbance levels (disturbed and less disturbed habitat) and the two seasons (dry and wet seasons) were both compared using Mann-Whitney U-test (Zar, 2010). Invertebrates species diversity of the present study for both in dry and wet seasons was computed using the Shannon Wiener diversity index, while its comparison was made using a special (t) test (Zar, 2010). The entire compositional analyses in this study was computed using the Paleontological Statistics software package (PAST) (Hammer et al., 2001) whereas figs. were sketched out using Microsoft excel sheet. Results and discussion The study collected 484,481 invertebrate individuals from the study sites, out of which 474,118 (97.9%) and 10,363 (2.1%) Formica exsecta and other invertebrate individuals, respectively, collected in the two habitat disturbance levels (the disturbed and less disturbed habitat) and two seasons (dry and wet seasons). The disturbed habitat had 259,357 Formica exsecta and 2,216 other invertebrate individuals whereas the less disturbed habitat had 214,761 Formica exsecta and 8,147 other invertebrate individuals (Table 1). The abundance of Formica exsecta was significantly higher in the disturbed habitat than in the less disturbed habitat (Fig. 2, Mann Whitney U = 131, p < 0.0004, n1 = 25, n2 = 25). Other invertebrates were significantly higher in the less disturbed habitat level than in the disturbed habitat level (Fig. 2, Mann Whitney U = 54, p < 0.0001, n1 = 25, n2 = 25). Fig. 2. The mean abundance of Formica exsecta and Other Invertebrates in the disturbed and less disturbed habitat levels in fragment of the Tanzania’s Coastal Forests. DH = Disturbed Habitat, LDH = Less Disturbed Habitat, Fe = Formica exsecta, OI = Other Invertebrates. J. Bio. & Env. Sci. 20 23 5 | Mohamed The dry season had 338,539 Formica exsecta and 4,003 other invertebrate individuals whereas the wet season had 135,579 Formica exsecta and 6,360 other invertebrate individuals (Table 1). The abundance of Formica exsecta was significantly higher in the dry than in the wet season (Fig. 3, Mann Whitney U= 4, p < 0.0001, n1= 25, n2= 25). Other invertebrates were not significant in terms of the differentials between the dry season and the wet season (Fig. 3, Mann Whitney U= 219, p= 0.071, n1= 25, n2= 25). The results indicate that Formica exsecta favoured high temperature of the dry season whereas the cool temperatures of wet season were more favourable to other invertebrate individuals (Richards & Windsor, 2007). It emerged that the wet environment ensured a well-developed canopy layer that found supporting terrestrial invertebrate such as ants, hence increasing its biomass, (Owens et al., 2022) other invertebrates in the present study possibly embraced similar trend. Formica exsecta and other aggressive Formicidae ants accounted for 99 percent of all the invertebrate individuals collected, which could also have lowered the diversity of other invertebrate in the dry season as was in the case of Mohamed (2023). Fig. 3. The mean abundance of Formica exsecta and other invertebrates in the dry and wet seasons in fragment of the Tanzania’s Coastal Forests. DS = Dry Season, WS= Wet Season, Fe= Formica exsecta, OI = Other Invertebrates. The total abundance of Formica exsecta insignificantly and negatively correlated with the total abundance of other invertebrates (r = -0.0012, p > 0.05). This result could be attributable to its higher abundance by more than 99 percent of all the collected invertebrate individuals as Mohamed (2016) had established to be similar on aggressive Solenopsis sp. In the two disturbance levels, they negatively correlated in the disturbed habitat with dominance of 54.7 percent of all the collected Formica exsecta (r= - 0.048) but positively correlated in the less disturbed habitat with dominance of 45.3% (r= 0.047). However, both results were insignificant (p> 0.05). This suggests that the higher the dominance of Formica exsecta, the more negative effects it would have on other invertebrates. Also, the abundance of Formica exsecta were found to negatively correlate with the abundance of other invertebrates during the dry season (71.4% dominance of all the collected Formica exsecta). Between the two disturbance levels, it was higher in the disturbed habitat with 54.7 percent dominance (r= -0.206) than in less disturbed habitat with 45.3 percent dominance (r= -0.002). However, the differences were not significant (p > 0.05). During wet season (with 28.6% dominance of all the collected Formica exsecta), the abundance of Formica exsecta significantly positive correlated with the abundance of other invertebrates (r= 0.436, p= 0.03) in the disturbed habitat but slightly negatively correlated in the less disturbed habitat (r= -0.205) though not statistically significant (p > 0.05). Furthermore, the present studies found that Formica exsecta were more active during the dry seasons with 71.4 percent followed by the disturbed habitat (54.7%). The less disturbed habitat accounted for 45.3 percent. Finally, the least active occurred during wet season (28.6%) for of all the Formica exsecta individuals collected. Essentially, all the collection efforts required the movement of the targeted organisms or else they could not have been captured. Implicitly, more collections imply being more active in the respective season or habitat disturbance level and vice-versa. J. Bio. & Env. Sci. 20 23 6 | Mohamed Table 1. The abundance of Formica exsecta and other Invertebrates in the two habitat disturbance levels and the two seasons in fragment of the Tanzania’s Coastal Forests. DH = Disturbed Habitat, LDH = Less Disturbed Habitat, DS = Dry Season, WS = Wet Season. Trap ID Formica exsecta Other Invertebrates Grand Total DH LDH Total DH LDH Total DS WS TOTAL DS WS Total DS WS TOTAL DS WS Total 1 3478 5790 9268 3683 2793 6476 15744 65 86 151 45 58 103 254 15998 2 5341 3125 8466 3982 2878 6860 15326 131 94 225 70 127 197 422 15748 3 7285 3588 10873 4118 2948 7066 17939 85 73 158 286 98 384 542 18481 4 6188 3027 9215 5286 2639 7925 17140 75 104 179 160 115 275 454 17594 5 7209 3973 11182 7560 2453 10013 21195 83 82 165 282 314 596 761 21956 6 6124 2120 8244 5377 1239 6616 14860 10 85 95 457 862 1319 1414 16274 7 5953 2203 8156 4068 1780 5848 14004 13 16 29 74 32 106 135 14139 8 7457 3443 10900 4766 2566 7332 18232 20 54 74 165 28 193 267 18499 9 8608 4113 12721 6247 3289 9536 22257 56 37 93 51 34 85 178 22435 10 7764 3183 10947 5052 2291 7343 18290 38 44 82 31 56 87 169 18459 11 8541 1697 10238 4616 2360 6976 17214 27 41 68 111 56 167 235 17449 12 7750 1872 9622 5985 2298 8283 17905 13 31 44 74 96 170 214 18119 13 7928 2546 10474 4314 1040 5354 15828 24 25 49 37 371 408 457 16285 14 6697 2409 9106 6839 1277 8116 17222 17 17 34 66 183 249 283 17505 15 6589 2899 9488 6888 1468 8356 17844 40 21 61 95 425 520 581 18425 16 7582 2095 9677 6372 2049 8421 18098 29 21 50 38 431 469 519 18617 17 6135 2927 9062 6060 2989 9049 18111 69 36 105 34 67 101 206 18317 18 6632 2632 9264 6225 1605 7830 17094 16 31 47 59 31 90 137 17231 19 7867 2064 9931 5498 3005 8503 18434 11 35 46 89 211 300 346 18780 20 9061 4165 13226 5412 1530 6942 20168 24 30 54 52 485 537 591 20759 21 8319 2055 10374 6603 2699 9302 19676 18 25 43 272 202 474 517 20193 22 10664 2150 12814 8984 2239 11223 24037 52 23 75 50 131 181 256 24293 23 10096 2000 12096 9754 3681 13435 25531 22 41 63 111 129 240 303 25834 24 8121 3516 11637 10213 5466 15679 27316 36 36 72 146 437 583 655 27971 25 8872 3504 12376 8376 3901 12277 24653 114 40 154 60 253 313 467 25120 Total 186261 73096 259357 152278 62483 214761 474118 1088 1128 2216 2915 5232 8147 10363 484481 Species Diversity A total of 134 species were collected out of which 12 were identified at the species level and 122 as morpho species. Formica exsecta dominated by accounting for 97.9 percent of all the 484,481 invertebrate individuals collected. The rest having less than 1.2 percent each. A total of 87 families and 18 orders were collected, out of which the family Formicidae and order Hymenoptera each led by more than 99% of all the collected individuals (Table 2) relating to study conducted by Popescu et al. (2021) who also found greater representation of the Formicidae individuals. The disturbed habitat had a higher number of individuals (n= 261,573) than the less disturbed habitat (n= 222,908). On the other hand, the disturbed habitat had a lower diversity and number of species (H= 0.078, Taxa S= 110) than the less disturbed habitat (H= 0.224, Taxa S= 119) the difference was significant (t= -55.03, df = 3.8655E05, p =0). The higher number of taxa and diversity in the less disturbed habitat level corresponded with the results of Niba & Yekwayo (2016) who had found higher taxa in natural forests and grasslands with less distortion coupled with higher diversity, which could have been contributed by the lower abundance of aggressive Formica exsecta relative to the disturbed habitat, which raised its higher abundance by more than 99% of all the individuals collected in the disturbed habitat. J. Bio. & Env. Sci. 20 23 7 | Mohamed Table 2. Taxonomic profile, abundance and diversity of Invertebrate taxa sampled in the two habitat disturbance levels and the two seasons in fragment of the Tanzania’s Coastal Forests. DH= Disturbed Habitat, LDH= Less Disturbed Habitat, DS= Dry Season, WS= Wet Season. Taxonomy Data Habitat Disturbance Levels Seasons TOTAL Order Family Morpho Species & Species Names DH LDH DS WS Araneae Agelenidae Agelenopsis sp. 69 67 49 87 136 Lycosidae Lycosid sp. 10 9 6 13 19 Salticidae Salticid sp. 35 30 24 41 65 Thomicidae Thomicid sp. 15 12 4 23 27 Sparassidae Sparassid sp. 1 4 1 4 5 Corinnidae Corinnid sp. 169 130 123 176 299 Mimetidae Mimetid sp. 2 3 1 4 5 Pholcidae Pholcus sp. 3 4 5 2 7 Blattodea Blattidae Periplaneta americana 105 185 151 139 290 Periplaneta sp. 13 45 43 15 58 Blattid sp. 8 21 23 6 29 Blatta sp. 85 146 76 155 231 Blaberidae Blaberid sp.1 17 13 20 10 30 Blaberid sp.2 10 23 31 2 33 Blaberus sp. 8 16 22 2 24 Blattellidae Blattellid sp. 15 19 20 14 34 Blattella sp. 13 28 19 22 41 Coleoptera Trogidae Omorgus sp. 1 1 2 0 2 Passalidae Passalid sp. 0 6 1 5 6 Tenebrionidae Tenebrionid sp.1 7 9 3 13 16 Tenebrionid sp.2 5 5 3 7 10 Tenebrio molitor 2 2 1 3 4 Cossyphus sp. 2 1 1 2 3 Coccinellidae Coccinellid sp. 17 14 2 29 31 Carabidae Carabid sp.1 14 18 11 21 32 Carabid sp.2 3 7 3 7 10 Carabid sp.3 1 4 1 4 5 Carabid sp.4 1 2 1 2 3 Crepidogaster sp. 23 27 22 28 50 Histeridae Histerid sp. 1 0 1 0 1 Chrysomelidae Chrysomelid sp.1 19 4 1 22 23 Chrysomelid sp.2 11 3 0 14 14 Dicladispa sp. 2 2 1 3 4 Scarabaeidae Scarabaeid sp.1 5 5 8 2 10 Scarabaeid sp.2 1 4 5 0 5 Garreta azureus 4 2 0 6 6 Garreta sp. 3 2 0 5 5 Hypopholis sommeri. 1 2 0 3 3 Serica brunnea 0 1 0 1 1 Phalacridae Phalacrid sp. 0 1 1 0 1 Elateridae Elaterid sp. 0 1 1 0 1 Nitidulidae Nitidulid sp. 45 27 0 72 72 Curculionidae Curculionid sp. 8 7 0 15 15 Drilidae Drilid sp. 1 0 0 1 1 Staphylinidae Staphylinid sp. 1 2 0 3 3 Cerambycidae Cerambycid sp. 1 0 0 1 1 Dermaptera Forficulidae Forficulid sp. 4 3 6 1 7 Labiduridae Labidurid sp. 4 4 0 8 8 Diptera Muscidae Muscid sp.1 10 1 6 5 11 Muscid sp.2 5 6 0 11 11 Calliphoridae Lucilia sericata 2 5 1 6 7 Phoridae Phorid sp. 7 0 2 5 7 Sciaridae Sciarid sp. 3 0 2 1 3 Drosophillidae Drosophila sp. 67 182 20 229 249 Platystomatidae Amphicnephes sp. 6 7 0 13 13 Pyrgotidae Pyrgotid sp. 0 1 0 1 1 Stratiomyiidae Stratiomyiid sp. 1 0 0 1 1 J. 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Sci. 20 23 8 | Mohamed Taxonomy Data Habitat Disturbance Levels Seasons TOTAL Order Family Morpho Species & Species Names DH LDH DS WS Sarcophagidae Sarcophagid sp. 0 2 0 2 2 Culicidae Aedes sp. 0 1 0 1 1 Embiidina Oligotomidae Oligotomid sp. 0 8 7 1 8 Geophilomorpha Geophildae Geophilus sp. 10 13 11 12 23 Haplotaxida Lumbricidae Lumbricid sp. 7 6 0 13 13 Hemiptera Reduviidae Reduviid sp.1 5 5 3 7 10 Reduviid sp.2 5 3 1 7 8 Reduviid sp.3 0 2 1 1 2 Reduviid sp.4 1 2 0 3 3 Pseudococcidae Pseudococcid sp. 65 37 41 61 102 Coreidae Coreid sp. 2 10 1 11 12 Fulgoridae Fulgorid sp. 2 1 3 0 3 Lygaeidae Lygaeid sp.1 4 8 4 8 12 Lygaeid sp.2 1 4 1 4 5 Pyrrhocoridae Dysdercus sp.1 8 10 1 17 18 Dysdercus sp.2 2 2 0 4 4 Miridae Mirid sp. 0 2 2 0 2 Tingidae Tingid sp. 1 0 0 1 1 Cixiidae Cixiid sp. 0 1 0 1 1 Scutelleridae Scutellerid sp. 2 0 0 2 2 Pentatomidae Pentatomid sp. 0 1 0 1 1 Alydidae Alydid sp. 0 1 0 1 1 Cydnidae Pangaeus sp. 3 4 0 7 7 Aradidae Aradid sp. 0 1 0 1 1 Hymenoptera Formicidae Formica exsecta 259357 214761 338539 135579 474118 Polyrhachis gagates 31 61 85 7 92 Pachycondyla sp. 23 35 41 17 58 Messor capensis 155 450 503 102 605 Lepisiota sp.1 22 33 7 48 55 Tetraponera sp. 50 115 132 33 165 Lepisiota sp.2 36 7 10 33 43 Formicid sp.1 131 600 723 8 731 Formicid sp.2 447 5166 1341 4272 5613 Formicid sp.3 0 2 1 1 2 Eumenidae Eumenid sp. 3 3 2 4 6 Mutillidae Ronisia sp. 1 1 2 0 2 Mutillid sp. 1 2 2 1 3 Sphecidae Chlorion maxillosum 1 1 2 0 2 Sphecid sp. 0 1 0 1 1 Pompilidae Pompilid sp. 1 4 1 4 5 Masaridae Masarid sp. 0 2 1 1 2 Ichneumonidae Ichneumon sp. 1 0 0 1 1 Halictidae Halictid sp. 1 0 0 1 1 Pteromalidae Pteromalid sp. 1 0 0 1 1 Evaniidae Evaniid sp. 1 1 0 2 2 Braconidae Braconid sp. 0 2 0 2 2 Tiphiidae Tiphiid sp. 0 2 0 2 2 Isoptera Termitidae Macrotermes sp. 18 50 58 10 68 Julida Julidae Cylindroiulus sp. 39 36 54 21 75 Julid sp. 23 30 34 19 53 Lepidoptera Psychidae Psychid sp.1 10 4 4 10 14 Psychid sp.2 3 2 0 5 5 Hepialidae Hepialid sp. 2 2 2 2 4 Nymphalidae Nymphalid sp.1 0 2 1 1 2 Nymphalid sp.2 7 8 2 13 15 Tineidae Tineid sp. 2 0 0 2 2 Noctuidae Noctuid sp.1 2 1 0 3 3 Noctuid sp.2 0 1 0 1 1 Sphingidae Sphingid sp. 0 1 0 1 1 Tortricidae Tortricid sp. 0 2 0 2 2 Satyridae Satyrid sp. 1 0 0 1 1 Mantodea Thespidae Thespid sp. 2 0 2 0 2 J. 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Sci. 20 23 9 | Mohamed Taxonomy Data Habitat Disturbance Levels Seasons TOTAL Order Family Morpho Species & Species Names DH LDH DS WS Mesogastropoda Pomatiasidae Tropidophora sp. 2 2 1 3 4 Orthoptera Acrididae Acridid sp. 20 13 13 20 33 Acrotylus sp. 7 5 5 7 12 Cannula grasilis 4 1 1 4 5 Gryllidae Cophogryllus sp.1 111 138 111 138 249 Cophogryllus sp.2 44 78 54 68 122 Brachytrupes sp. 0 1 1 0 1 Gryllidae sp. 1 1 2 0 2 Anostostomatidae Anostostomatid sp. 3 1 3 1 4 Tettigoniidae Tettigoniid sp. 1 0 0 1 1 Solifugae Solpugidae Solpugid sp. 2 1 0 3 3 Stylommatophora Subulinidae Pseudoglessula sp. 3 7 0 10 10 Streptaxidae Gullella sp. 1 4 1 4 5 Gonaxis sp. 1 2 0 3 3 Urocyclidae Urocyclid sp. 17 19 1 35 36 Total Number of Individuals (N) 261573 222908 342542 141939 484481 Total Number of Taxa (S) 110 119 89 122 134 Shannon Wiener Diversity Index (H’) 0.0779 0.2241 0.0931 0.2656 0.152 Contrary to many findings (see, for example, Zeng et al., 2023; Owens et al., 2022), the dry season had a higher number of individuals (n = 342,542) than the wet season (n = 141,939), possibly, due to the overdominance of aggressive Formica exsecta. Indeed, the Formica exsecta collected accounted for more than 98 percent of all the individuals in the dry season, which naturally lowered the diversity and number of species (H = 0.093, Taxa S = 89) in comparison to the wet season (H = 0.266, Taxa S = 122). The difference was significant (t = -53.081, df = 1.9746E05, p = 0) primarily because several invertebrates are incapable of enduring the hostility of the Formicidae ants (Mohamed, 2023), hence resulting into their displacement. The higher invertebrate biodiversity in the wet season correlate with both Zeng et al. (2023) and Owens et al. (2022) who similarly found high levels of diversity and biomass of terrestrial invertebrates such as termites and ants. Also, the wet season supports the sprouting of a variety of trees and rotten woods (Schowalter et al., 2021) fostering ecosystem productivity, which created amenable environments for many invertebrate individuals and, hence, the higher taxa numbers and diversity also registered in this study. Conclusion Despite the difficulties inherent in estimating invertebrate biodiversity, still are worldwide known as a major component in terrestrial ecosystems (Dopheide et al., 2019). Therefore, the present study provides a unique foundation for estimating invertebrate biodiversity in the Tanzania’s Coastal Forests (TCFs) and the onset of invasive Formica exsecta with their respective ecological effects. In fact, this study has demonstrated that TCFs have a higher number of invertebrate species and diversity, hence raising the possibility of higher litter decomposition. This conclusion is consistent with Zeng et al. (2023) who had reported higher invertebrate diversity together with other factors such as warm, humidity and acidity being highly associated with forest litter decompositions, hence directly ensuring TCFs sustainability and continuity. The ongoing deterioration of TCFs may have many ecological effects including the invasion of non-native flora and fauna such as Maesopsis eminii and Formica exsecta, respectively, as they are both enticed by low canopy cover (Mwendwa et al., 2019; UK-Wood Ant (UKWA), n.d.). Such threats to the TCFs can endangers enormous endemic wildlife. Implicitly, there is a need for conservation efforts that can integrate both private and public-owned small and large-scale fragments before it was too late. Acknowledgements I wish to acknowledge sincerely the late Prof. R. B. M. Senzota for agreeing to conduct this study at then his