Projects in our lab explore a variety of topics. Click on the links below for more details.
A) Pollen quantity and quality: plant responses to stress
Recent honeybee declines may be influenced by pollen/nectar quality that compromise a bees’ ability to cope with environmental challenges, including disease and stress. Plants facing drought compromise floral trait expression which in turn can affect bee health. We are studying how drought stress in canola (Brassica napus) affects the floral reward quantity and quality. We are also monitoring the quality of bee hive pollen when foraging on crops under abiotic stress
B) Floral chemicals
Plant-pollinator mutualism go beyond floral traits and pollinator behavior. Pollinators have evolved to take advantage of diverse floral chemicals. Increasing our knowledge of the chemical relationships between bees and plants is an important step towards understanding the intricacies of hive function and honeybee colony management. Ongoing studies aim to understand the role of key phytochemicals in promoting honeybee health
C) Honeybee decision making:
Animals continuously choose among various available options to exploit the most profitable resource. They also need to keep themselves updated about the values of all available options, since their relative values can change quickly due to depletion or exploitation by competitors. By presenting foragers of the honey bee Apis cerana with choice tests in a foraging arena and recording their behavior, we investigate possible sampling and decision rules that the foragers use to choose one option over another and to track other options.
Naug D, Arathi HS. 2007. Sampling and decision rules used by honey bees in a foraging arena. Animal Cognition, 10: 117-124.
Signaling systems operating in plant–pollinator interactions are among the most highly co-evolved, with plants using a variety of floral signals to attract pollinators. We used a standard dual-choice experimental protocol to show that honeybees display a receiver bias for exaggerated size and color contrast – two important components of floral signals— even when such signals do not indicate quality.
Naug D, Arathi HS. 2007. Receiver bias for exaggerated signals in honeybees and its implications for the evolution of floral displays. Biology Letters, 3: 635-637.
D) Honeybee Hygienic Behavior
Hygienic behavior performed by middle-aged worker bees is an important task in colonies of the honey bees. The behavior has a strong genetic basis with bees in the hygienic line when assayed for the behavior are capable of cleaning freeze killed brood within 48 hours while bees in the non-hygienic line take over 6 days to clean. The behavioral sequence involves detecting diseased brood in the larval and pupal stages and removing all such infected brood thereby decreasing the incidence of infection. The expression of hygienic behavior in colonies depends on the proportion of bees from the hygienic line.
Arathi HS, Burns I, Spivak M. 2000. Ethology of Hygienic Behaviour in the Honey Bee Apis mellifera L. (Hymenoptera: Apidae): Behavioural Repertoire of Hygienic Bees. Ethology, 106: 365-379.
Arathi HS, Spivak M. 2001. Influence of colony genotypic composition on the performance of hygienic behaviour in the honeybee, Apis mellifera L. Animal Behaviour, 62: 57-66.
Arathi HS, Ho G, Spivak M. 2006. Inefficient task partitioning among nonhygienic honeybees, Apis mellifera L., and implications for disease transmission. Animal Behaviour, 72: 431-438.
A) Urban Bee Diversity
Beginning in 2016 through the Native Bee Watch we are assessing the bee diversity and abundance in the City of Fort Collins through the involvement, education, and engagement of citizens with a larger goal of assisting the city in the development of bee-friendly habitats and pollinator management protocols. Through citizen science initiatives we will increase awareness, research capacity, and educate citizens on scientific issues. We aim to create positive behavior change in the citizen community by engaging them to help direct policy and protocols as a part of the City of Fort Collins’ Nature in the City Strategic Plan.
B) Bee Diversity in Farms
Growing Genetically Modified Herbicide Tolerant (GMHT) cultivars indirectly contributes towards pollinator declines through habitat degradation. Extensive use of herbicide in and near fields with herbicide tolerant cultivars eliminate weedy and semi-natural habitats around agricultural fields which consist of non-crop flowering plants (‘weeds’) that offer forage resources after crop bloom is completed. Planting pollinator strips is one approach to improve floral diversity and nutritional options for bees enabling spillover from crop fields. Our study measured the efficacy of pollinator strips near GMHT canola fields by measuring bee pollinator diversity and abundance in canola fields and an adjoining pollinator strip with native flora.
O’Brien, C.** and Arathi, H.S. Bee pollinator diversity and abundance near genetically modified canola fields In Press
C) Bee Diversity in Hemp
Hemp is an attractive crop not just to humans but a diversity of bees too. Look out for our publication documenting bee diversity in hemp!
D) Bees in Rangelands
Ongoing projects are aimed at describing bee pollinator diversity in rangelands and crop lands that are currently under the Conservation Reserve Program. Other studies are exploring the effects of cover crops and grazing on the activity and abundance of ground nesting bees.
A) Floral traits and pollination
The showy corolla of flowers is generally considered an adaptation to attract pollinators. However, there may be additional benefits that plants derive as we demonstrate that corolla morphology plays a critical mechanical role in both outcrossing and self-fertilization. In the absence of pollinators, the lower portion of the corolla facilitates autogamy by retaining pollen released from the anthers.
Arathi HS, Kelly JK. 2004. Corolla Morphology Facilitates Both Autogamy and Bumblebee Pollination in Mimulus guttatus. International Journal of Plant Sciences, 165: 1039-1045.
Kelly JK, Holeski LM, Arathi HS. 2008. The genetic correlation between flower size and water use efficiency in monkeyflowers. Evolutionary Ecology Research, 10: 147–152.
Kelly JK, Arathi HS. 2003. Inbreeding and the genetic variance in floral traits of Mimulus guttatus. Heredity, 90: 77-83.
Quinn CF, Prins CN, Freeman JL, Gross AM, Hantzis LJ, Reynolds RJB, in Yang S, Covey PA, Bañuelos GS, Pickering IJ, Fakra SC, Marcus MA, Arathi HS, Pilon-Smits EAH. 2011. Selenium accumulation in flowers and its effects on pollination. New Phytologist, 192: 727-737.
B) Floral longevity and delayed selfing
Arathi HS, Rasch A**, Cox C**, Kelly JK. 2002. Autogamy and floral longevity in Mimulus guttatus. International Journal of Plant Sciences, 163: 567-573.
Jorgensen R**, Arathi HS. 2013. Floral longevity and autonomous selfing are altered by pollination and water availability in Collinsia heterophylla. Annals of Botany, 112: 821-828.
C) Plant reproductive strategies
Arathi HS, Mei A. **, Smith TJ**. 2016. Reproductive functions as affected by abiotic stress in Collinsia heterophylla, a hermaphroditic annual flowering plant. In prep.
Mudd SJ**, Arathi HS. 2012. Image Analysis Protocol for Detecting and Counting Viable and Inviable Pollen Grains. Journal of Plant Studies, 1: 158-167.
Arathi HS. 2012. A comparison of dispersal traits in dandelions growing in urban landscape and open meadows. Journal of Plant Studies, 1: 40-46.
Arathi HS. 2011. Selective embryo abortion in a perennial tree-legume: a case for maternal advantage of reduced seed number per fruit. Journal of Plant Research, 124: 675-681.
Bedhomme Sp, Bernasconi G, Koene JM, Lankinen Ã, Arathi HS, Michiels NK, Anthes N. 2009. How does breeding system variation modulate sexual antagonism? Biology Letters, 5: 717-720.
Arathi HS, Ganeshaiah KN, Shaanker RU & Hedge SG (1999) Seed abortion in Pongamia pinnata (Fabaceae). American Journal of Botany 86: 659-662.
Arathi HS, Ganeshaiah KN, Shaanker RU & Hegde SG (1996) Factors affecting embryo abortion in Syzygium cuminii (L.) Skeels (Myrtaceae). International Journal of Plant Sciences 157: 49-52.