Introduction

Rocky terrain anywhere in the world, is considered inhospitable and impoverished habitats due to the insufficiency of soils and poor water holding capacity even in heavy rainfall zones. High levels of solar insolation, to which such terrain often get subjected to, cause immoderate rise and fall in diurnal temperature. Large stretches of low-level laterite hills and plateaus abutting the Western Ghats are characteristic of the western coastal tract of India, especially in the district of Uttara Kannada. Such landscape was considered infertile and of poor productivity. However, a spurt of interest in recent years has brought out the presence of many rare herbs growing on laterites of south-west India. These include also new species such as Rotala malabarica, Nymphoides krishnakesara, Justicia ekakusuma, Lepidagathis keralensis, Eriocaulon sivarajanii, E. kannurense, E. madayiparnese, Lindernia madayiparense etc., discovered first from the Malabar coastal hills etc^1-8. Such findings are despite heavy human impacts like biomass harvests, cattle grazing, extraction of building stones and overall neglect such coastal habitats have been facing. Find of new species like Eriocaulon belgaumensis, and Dipcadi goaense from the laterite hills of Karnataka and Goa respectively indicates that these habitats could be veritable hot spots for rare herbs^{9, 10}. The laterite capped high altitude hills of Maharashtra Western Ghats, are no exception^11-15 in yielding a good number of new and rare species. Rao et al.¹⁶ have provided a comprehensive account of the richness of monsoon herb flora of the laterite wetlands and meadows of Uttara Kannada implicating also the support such flora might provide to insect community prompting the current study.

Animal pollination is stated to benefit 87 out of the 124 leading food crops which the humans cultivate worldwide¹⁷. Insects are the most important pollinators of an estimated 70% of flowering plants, honeybees leading among them^18-20. Engel and Irwin²¹ reported a positive relationship between honeybee visitation rates and pollen deposits on the stigma. The frequencies of bee visitations on flowers are indeed related to the amount of seed setting and seed quality²². Hence, honeybees are considered keystone species for reproductive success of many plant species, implicating that their decline could spell disruption of plant-pollinator networks leading to possible extinction cascades^{23, 24}.

The threats that honeybees face worldwide due to excessive use of pesticides, habitat shrinkages and food scarcity are a matter of concern. Nourishment of honeybees is mainly dependent on nectar and pollen. Smith²⁵ reported that the bees with higher levels of body protein lived longer than those with lower levels, thereby implicating the importance of bee nutrition in apiary. Pokhrel et al.²⁶ had reported death of forager bees in Nepal caused by intermittent rains related nectar scarcity during April-May and washing away of pollen by heavier rains in July. Decline in bee flowers during rainy season was stated to be the reason for adverse impact on Apis cerana population in Chitwan, Nepal. Strength of bee colony weakening during mid-November to February at Kabre in Dolakha district of Nepal has been attributed to the dearth of forage plants^{27, 28}.

Much less is known in India, one of the major honey producing countries of the world, on the off-season, specially the monsoon period, nectar/forage resources of honeybees, a big lacuna with wider implications not just on honey production but also on crop production²⁹. In the Uttara Kannada district, despite a forest cover of about 70% of its land area exceeding 10,000 km², and other forms of greenery elsewhere, the paucity of flowering in forests from June to September, a period of high intensity monsoon rains, is a critical time for honeybees. In the district, well-known for its forest honey, the beekeepers in the Western Ghats terrain feed the domesticated bees with jaggery solution or its mixture with gram flour³⁰. During the monsoon of 2012, while inventorying the forage resources for honey bees in the district, we noticed congregations of bees and butterflies, in the coastal laterite hills and plateaus, flush with tiny herbs in bloom. This observation prompted us to undertake the current study aimed at the honey bee community meeting its off-season forage needs from the characteristic laterite flora, with special focus on the visitation rates of bees on two of the most prolific monsoon herbs, namely Utricularia spp., and Eriocaulon spp., and two others viz. herbaceous Impatiens spp., and a thorny shrub F. indica.