PRELIMINARY SURVEY OF Macrotermes bellicosus INFESTATION ON PUBLIC UTILITY POLES IN EKOSODIN COMMUNITY, NIGERIA; IMPLICATION FOR UNINTERRUPTED ELECTRICITY SUPPLY

ermite’s infestation on wooden poles is becoming worrisome to home and business owners given the public reliance on such poles for electricity supply. Here electric poles were surveyed in Ekosodin community using visual observation of randomly tagged functional poles to evaluate the extent of infestation and the functional state of the poles relative to the infestation, alongside the economic cost of replacing the damaged poles in three predetermined areas (zones) within the community, based on the scale of human development. A total of 164 poles were surveyed, 26.8% (44) of which were concrete poles. The survey showed that the infested wooden poles outnumbered the ‘unaffected’ ones as more than two-third of the 120 wooden poles surveyed were infested as opposed to the uninfested ones (30.83%). The termite implicated for this impact was Macrotermes bellicosus Smeathman (Blattodea: Termitidae) and its impact visibly eroded the base and structural strength of affected poles, thus contributing to the tilting (53%) of the infested poles, which are load-bearing poles in dire need of replacement. Replacement cost for the affected poles within the community was estimated alongside the cost of pre-installation treatments of wooden poles, and the use of concrete poles -though more expensive than wooden poles-which could mitigate termites’ impacts on the utility poles were recommended. Frequent replacement with untreated wooden poles may heighten the pressure on our natural resources through lumbering for pole production; besides the attendant threats and dangers of pole wreckage on people, homes and other facilities such as electricity transformers.


INTRODUCTION
The tropical rainforests are endowed with diverse flora, and rich in cellulose -a major food for termites.With a growing proportion of the tropics being under increasing pressure from urbanization, a correlate of human population growth, the unending reliance on plant materials in some aspects of societal development increases the redistribution of cellulose materials from the wild to human settlements.Such areas largely rely on cellulose materials for home constructions and other purposes.Our increasing reliance on these cellulose materials following urbanization and land-use patterns for agricultural purposes is accompanied by increased human-termite encounters and resource utilization (Demissie et al., 2019;Debelo, 2020;Novita et al., 2020).
Termites are widely distributed with more than a thousand species of the over 2600 known species found in Africa (UNEP, 2000) and West Africa is endowed with a rich fauna of termites that include several genera which include: Ancistrotermes, Macrotermes, Microtermes, Odontotermes and Cubitermes: (UNEP, 2000; Agunbiade et al., 2009;Mbah and Chagbe, 2010).Termites depend on the protozoan (biflagellates), bacteria and basidiomycete fungus for cellulose digestion -a means of rendering vital ecosystem services (Bland and Jacque, 1978;Ibrahim and Adebote, 2012;Ali et al., 2021).
In urban areas, termites infest several products of cellulose from papers, even in printing press, to human dwellings, including agricultural products (Logan et al., 1990;Agunbiade et al., 2009;Mbah and Chagbe, 2010;Kumar and Pardeshi, 2011;Upadhyay, 2013;Demissie et al., 2019).The enormity of termite's impact is well known that the United States of America spends >$1 billion on their management annually, while China loses over $1 billion annually due to termite infestation (UNEP, 2000).Approximately >$100 million is spent on management and repairs in Australia (UNEP, 2000).However, the cost associated with termite damage in Nigeria remains largely unquantified.
Meanwhile, homes, public facilities and utility poles made from cellulose materials are increasingly deteriorating in the country following termite infestation.Here, termite's damage on public utility poles within an urbanized tropical space was surveyed to quantify the scale of termites' impacts with discussion on possible mitigation strategies.

MATERIALS AND METHODS
The survey was carried out at Ekosodin community (6° 24' 44.82"N, 5° 37' 41.556" E), a neighboring community to the University of Benin, which is situated at Ugbowo, Benin City, Nigeria.Ekosodin is predominantly a residential quarter mostly inhabited by low-and medium-income earners, who are largely associated with the university either as workers or students.
In this survey, the community was divided into six zones, out of which three (zone 1-3) were randomly selected for the study.In zone 1 and 2, three streets were surveyed by visual assessments of all the public utility poles, while four streets were surveyed in zone 3 on account of its size and scale of human development.Among the zones, zone 1 was farthest from the community centre with less than 40 residential buildings, and zone 2 was also situated outside the community centre, but had more human development than zone 1.Unlike zones 1 and 2, the third zone was situated at the centre of Ekosodin community with more human presence (as evident in the presence of over 90 houses).Thus, the scale of development was in the order of zone 1 < zone 2 < zone 3.
Close observations of the bases of wooden utility poles were conducted to identify infested or un-infested poles.The infested poles were further grouped into 3 categories: (i) heavily infested; (ii) moderately infested; and (iii) slightly infested.The costs of poles were obtained from the open market where utility poles are sold to unravel the rationale behind people's preference for the different poles used in the community.The average service life (i.e., the AJHSE 3(1) Egbon, 2022 | 63 replacement time) of a wooden pole was obtained from twenty randomly interviewed residents.The management strategies adopted by the community in response to worn out poles were juxtaposed with pole replacement cost.
Workers of the termites found on randomly selected wooden poles were identified in the laboratory.

RESULTS AND DISCUSSION
Investigations on the extent of impacts caused by a species of subterranean termites on wooden utility poles revealed that the 60% of the inspected poles were infested (Table 1 and 2).The results showed their remarkable preference for, and scale of infestation on, wooden poles, albeit at a local scale (in Ekosodin).Termite preference for woods and wood susceptibility varies across plant species (Peralta et al., 2004;Mbah and Chagbe, 2010;Muthike and Ali, 2021).
Coptotermes formosanus, for instance, prefers light and soft woods to heavy and hard ones (Bultman, 1979;Femi-Ola et al., 2007), but see Waller et al. (1990), where differential density in pine and mahogany did not mean much in affecting termite's preference.Wood treatments lessen pole susceptibility and loss of structural integrity arising from the temporal effects of deteriorating agents (e.g., fungi, termites, and moisture) that are capable of truncating their service lives, especially for load-bearing poles that are continually bedeviled by externalities such as windstorm and wildfires (Morrell, 2016;Wang, 2019;Ali et al., 2021;Muthike and Ali, 2021).
Soft woods such as Eucalyptus robusta and Pinus spp.are more consumed by subterranean termites than those of intermediate hardness such as E. pellita and E. urophylla (Peralta et al., 2004).Meanwhile, the different plant species used for utility poles in Ekosodin (and perhaps Nigeria) largely remain undocumented, but the use of Eucalyptus species for poles, and by termites are well known (Mbah and Chagbe, 2010;Muthike and Ali, 2021).The results here showed that majority of the wooden poles in Ekosodin were heavily impacted by termites as more than two-third of the poles were infested (Table 2), as opposed to 30.83% of uninfested ones.Undoubtedly, the uninfested poles may also become infested later, on account of age-dependent and deterioration-driven fragility arising from fungal and termite attacks.Across the three predetermined surveyed zones, the termite-infested poles out-numbered the uninfested ones -an observation that aligns with the views enunciated by Forschler (2000) that urbanization and changing land-use patterns increase human-termite encounters.From the three categories of infested wooden poles (Table 3), the heavily infested poles were reckoned to be 43%.The community feedback as obtained from the twenty respondents revealed that the average replacement time for these poles was 5 years (Table 4).The absence of early replacement strategy following termites' damage (especially the heavily infested ones) left in its wake forty four tilting wooden poles alongside thirty nine cases of sagging electric conductors (commonly known as electric cables) (Table 4).In some instances, these infested poles were re-used (re-pegged) after rupture -a practice that exacerbates the sagging effect of the electric conductors.
Untreated wooden poles are seemingly vulnerable to termite infestation as they are pegged through different soil depths (from the topsoil to about 3 feet depth) -all of which are within the termites' habitable space (e.g., 0-15 cm of the topsoil: Abe and Mastumoto, 1979;or 20-30 cm: Thian-Woei et al., 2012 andBandara et al., 2021).
Observations here conform to Abe and Mastumoto (1979)  the latter in southern Nigeria largely remain unknown, random sampling of the culpable species in this study implicated M. bellicosus.However, relying on visual assessment to profile the composition of termite species on poles is rife with several challenges given the insect's cryptic galleries and activities, which sometimes elude the assessors except through destructive sampling (see Bandara et al., 2021).To effectively profile the species and adequately plan a management strategy, further studies involving destructive sampling are required, and all infected poles may have to be decommissioned and replaced accordingly.
The management practices employed by the inhabitants in the surveyed area are: i). the use of concrete reinforcements at the bases of infested poles (see Plate 1a-e), which does not necessarily halt the termites' activities as the poles retain their footholds in the soil albeit at a much lower depth; and ii). the use of wooden reinforcements (Table 4; Plate 1d).Whilst the use of concrete reinforcements may prolong the service life of infested poles ephemerally, the use of wooden bracings (plate 1d) is not any better.Meanwhile, anecdotal claims (from some respondents) unravel some misconceptions that urinating around the base of an affected pole repels the termites.
Timber deterioration is complexly woven with moisture availability (Morrell, 2016;Bandara et al., 2021) and such reinforcement and speculated means of repelling termites could, in fact, delay the decommissioning and replacement of structurally compromised poles.
Probably, the people's choices for pole replacement and type (wooden or concrete) (Muthike and Ali, 2021) are cost-driven as concrete poles are more expensive than the untreated or poorly treated poles.Such economic factor may explain the much higher use of untreated poles than the others (Table 5); unbeknown to the end-users that AJHSE 3(1) Egbon, 2022 | 65 untreated or poorly treated poles have additional hidden cost of shorter service life and poorer resistance to fungi and termites than others (Gezer et al., 2015).Treated poles are not entirely desirable given the toxic footprints of their preservatives (e.g., Pentachlorophenol) (Harriot, 2014;Coles et al., 2014).With no known hazards, alternatives such as wood vinegar and botanicals may effectively deter subterranean termites (Oladipo-nee Ajayi et al., 2020;Kadir et al., 2021).Nonetheless, botanical-synthesizing plants (e.g., Azadirachta indica) with termiticidal properties and the synthetic creosote preservatives are amenable to termites and their associated microbes respectively (Mbah and Chagbe, 2010;Oladipo-nee Ajayi et al., 2020;Ali et al., 2021); thus discounting their long-term efficacy.
The pole-replacement drive in a typical peri-urban community (e.g., Ekosodin), that is largely inhabited by low-to-medium income earners, is poor given their inclination towards relying on makeshift reinforcement, bracings and fragile poles.Such proclivities dubiously prolong the service life of spent poles and delay their replacement time, which the termites have to five years (Table 4), whereas treated poles can attain thirty to eighty years in service or less time due to regional peculiarities (Gezer et al., 2015;Morrell, 2016;Darestani and Shafieezadeh, 2019).In fact, 22% of the wooden poles studied were reinforced with concrete while 6% were braced with woods, and a tenth of the poles were reused (Table 4); simply to circumvent the replacement cost and frequency.The ensuing makeshift tendencies are inseparable from the monetary cost that comes with a premium on 'treated' and concrete poles (Table 5).For multiple replacements, the premiums on the treated and/or concrete poles fuel the replacement drag exhibited by the community.

CONCLUSION
In sum, given the continual threats and associated dangers of pole wreckage (especially during the windy wet seasons) arising from structurally-compromised poles, the use of untreated poles should be discontinued to save the money, time and energy spent in pole replacements.Besides, using treated wooden and concrete poles can lessen the attendant ecological burden arising from soil erosion and deforestation on forest resources on account of unabated lumbering for pole production and other societal needs.Without key strategic plans to manage the notorious species of termites on utility poles (and other sundry wood structures), the nation's envisioned uninterrupted power supply to its citizens, home and business owners and sustainable resource utilization would remain unattainable.Against these backdrops and a need for efficient and sustainable use of natural resources, structural pest management and damage assessment should be prioritized nationwide to minimize, inter alia, the safety concerns arising from fragile poles that are worthy of decommissioning.

*
Physical characteristics of the bases of different termite-infested poles: a, b, c and e show the characteristic signs of termite actions while d is a typical concrete re-enforcement used by the residents Table 5: Current value of different poles in Nigerian Dollar equivalent ($1) = ₦500; ᶲHigh tension poles †Low tension poles

Table 1 :
Proportion and status of public utility poles in Ekosodin community

Table 2 :
The degree of termite infestation on wooden poles in Ekosodin Quarters

Table 3 :
Categories of infested wooden poles

Table 4 :
Attendant effects of termite infestation and adopted management strategies