Kaz Ohashi
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kazohashilab.bsky.social
Kaz Ohashi
@kazohashilab.bsky.social
820 followers 600 following 110 posts
Pollinator foraging behavior and its consequences for floral ecology and evolution | Assistant Professor @UofTsukuba | AE @jpollecol.bsky.social | ohashilab.com
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kazohashilab.bsky.social
Glad to see the clear-wing hawkmoth (Cephonodes hylas) is back in our garden! The way they quickly and accurately find their food plants (Gardenia jasminoides) and lay eggs is simply mind-blowing. #Hawkmoths
A clear-wing hawkmoth (Cephonodes hylas) oviposits on a young shoot of Gardenia jasminoides, its larval host plant. The moth’s body is sharply lit against the glossy green foliage, emphasizing its fuzzy yellow thorax and striped abdomen. In mid-air, a clear-wing hawkmoth (Cephonodes hylas) hovers with wings outstretched.
May 6, 2025 at 11:36 AM
kazohashilab.bsky.social
A marmalade hoverfly on a multiflora-rose flower. I love photography as it constantly reminds me of the breathtaking beauty of the creatures that inhabit our world. #Hoverflies #NativeFliwers
A close-up photograph of a Rosa multiflora blossom being visited by a hoverfly, Episyrphus balteatus. The fly’s translucent wings and vivid orange-and-black striped abdomen contrast beautifully with the delicate white petals and bright yellow stamens of the flower.
May 6, 2025 at 11:21 AM
kazohashilab.bsky.social
A huge Gentiana zollingeri 😍 #NativePlants #Spring
A huge ground blue gentian with more than ten flowers.
April 15, 2025 at 8:51 PM
kazohashilab.bsky.social
Took a short walk around campus. Delighted to see a carpenter bee, a mason bee, a long-horned bee, and a mining bee! #Bees
A male carpenter bee hovers mid-air with its wings outstretched. Its body is robust, with a golden-brown thorax and a shiny, dark abdomen. A male mason bee is perched on the edge of a blue gentian flower. The bee has a reddish-brown, fuzzy thorax and a dark metallic greenish head. Its wings are translucent and neatly folded over its back. A male Eucera bee with very long antennae visits a cluster of blue gentian flowers. The bee is facing downward into one of the blossoms, its wings reflecting light. A female Andrena bee resting on a leaf with large yellow pollen cakes on its hind legs. Her body is also covered with pollen grains.
April 15, 2025 at 8:46 PM
kazohashilab.bsky.social
Arisaema urashima has started blooming near my house. Its thread-like appendix serves as a ‘guiding path’ for fungus gnats walking through the leaf litter. #Pollination #Ecology

See also: doi.org/10.1002/ecy....
A blooming Arisaema urashima. The plant displays its characteristic dark spathe and a long, thread-like appendix curling upward.
April 12, 2025 at 4:02 AM
kazohashilab.bsky.social
Always happy to see newly emerged long-horned male Eucera bees in spring 🌸🌼🐝 #Bees
Two male Eucera bees resting on bright green lance-shaped leaves. Close-up of a male Eucera bee on a green leaf, showing its fuzzy thorax, striped abdomen, and distinctive long black antennae.
April 11, 2025 at 1:47 AM
kazohashilab.bsky.social
#Bee-flies are back—now it really feels like spring!
Two bee-fly-like insects with fuzzy brown and yellow bodies are mating on a rough asphalt surface. Their wings are outstretched, and one insect is perched directly behind the other in alignment. A close-up side profile of two bee-fly-like insects mating on a textured ground. Their long proboscises are visible, and their fuzzy bodies and transparent wings are highlighted against the low-angle background.
April 7, 2025 at 9:22 AM
kazohashilab.bsky.social
To celebrate our grad student Kentaro Takagi's very first first-authored paper in @funecology.bsky.social, I ordered this fantastic personalized mug from ScienceGrit (sciencegrit.com). Look at the #bee 🐝 foraging on the artificial flowers! 🌸
A custom-made mug with an academic paper design. The left side of the mug features the title, abstract, and author name of a scientific article. The right side showcases an image of a bumble bee foraging on artificial flowers in an experimental setup, along with a graph displaying research results. The mug has an orange handle and rim, sitting on a wooden table with a black chair and green cabinets in the background.
March 7, 2025 at 2:25 AM
kazohashilab.bsky.social
Our latest paper led by Kentaro Takagi was featured on the cover of Functional Ecology! 🎉👏🐝🌸

"Realized flower constancy in bumble bees: Optimal foraging strategy balancing cognitive and travel costs and its possible consequences for floral diversity"

For full details: bit.ly/4bzIADN
The cover of the latest issue of Functional Ecology. The featured photo shows the indoor experiment using bumble bees (Bombus ignitus) and artificial flowers. The worker gathers sugar solution from an artificial “flower” made of a transparent acrylic jar with a circular-coloured paper attached to the inside.
March 5, 2025 at 12:22 PM
kazohashilab.bsky.social
Flower buds of Japanese butterbur (Petasites japonicus) popping out of the ground—like sleepy heads peeking out from their blankets. Guess what? Spring has arrived!
#Asters #Flowers #Wildflwerhour
A close-up photo of a Japanese butterbur (Petasites japonicus) bud emerging from the ground. The green, tightly packed flower buds are surrounded by fresh, bright green leaves, contrasting with the dry brown leaves and grass in the background. Sunlight highlights the textures and details of the plant, signaling the arrival of spring.
March 2, 2025 at 9:51 PM
kazohashilab.bsky.social
Flower buds of Japanese butterbur (Petasites japonicus) popping out of the ground—like sleepy heads peeking out from their blankets. Guess what? Spring has arrived!
#Asters #Flowers
A close-up photo of a Japanese butterbur (Petasites japonicus) bud emerging from the ground. The green, tightly packed flower buds are surrounded by fresh, bright green leaves, contrasting with the dry brown leaves and grass in the background. Sunlight highlights the textures and details of the plant, signaling the arrival of spring.
March 2, 2025 at 10:22 AM
kazohashilab.bsky.social
We propose a framework predicting how bees shift flower constancy w/ spp. mixing & trait similarities. Notably, constancy increases w/ trait differences only when spp. are highly mixed, suggesting a novel perspective: spatial mixing promotes the evolution and maintenance of floral diversity.
A figure showing how bees adjust their flower constancy based on environmental factors. It consists of four diagrams showing how travel costs (blue), cognitive costs (orange), and total costs (grey) change w/ flower constancy. The red inverted triangles show the optimal level of constancy that minimizes the total costs. When spp. are mixed in space, more constant foragers benefit from reduced cognitive costs but face higher travel costs from skipping more flowers of different spp. When spp have distinct traits, the optimal constancy is intermediate, balancing both costs, but when spp. are similar, cognitive costs are minimal, leading to lower constancy. In patchy environments, constant foragers reduce travel costs and still avoid cognitive costs, resulting in higher flower constancy, regardless of flower trait differences. These patterns match the results in our experiments on spp. mixing and flower color similarities.
February 22, 2025 at 7:55 AM
kazohashilab.bsky.social
Bees stay loyal to 1 flower sp. to avoid cognitive switching costs. We update this, showing bees reduce constancy to 25% as distinct colors mix and shift toward inconstancy w/ similar colors. So, constancy isn’t just about cognitive limits—it’s an optimal strategy balancing cognitive & travel costs!
(Left) A worker of Bombus ignitus collecting nectar from an array of artificial flowers where blue and yellow flowers are evenly mixed. (Right) Realized flower constancy in our experiments and simulations under three levels of spp. mixing. Gray circles represent results from the experiment w/ blue vs. yellow flowers (dissimilar color pair), and black circles represent those from the experiment w/ yellow vs. golden yellow flowers (similar color pair). Each red bar represents the 5th to 95th percentile range of 500 CI values generated by the simulation, assuming no cognitive costs but travel costs. Realized flower constancy dramatically decreases as flower spp. become more spatially mixed, especially when they look alike, suggesting this behavior is a dynamic optimal strategy rather than a static result of cognitive limitation.
February 22, 2025 at 7:55 AM
kazohashilab.bsky.social
Flower constancy helps pollinators avoid the cost of switching search images or handling skills. But in nature, where flowers grow in clusters, could it also increase travel costs? If you've ever wondered about this, check out our latest paper in @funecology.bsky.social #Ecology

bit.ly/3QtUVzK

(🧵)
The title of the paper published in Functional Ecology, "Realized flower constancy in bumble bees: Optimal foraging strategy balancing cognitive and travel costs and its possible consequences for floral diversity," authored by Kentaro Takagi and Kazuharu Ohashi.
February 22, 2025 at 7:54 AM
kazohashilab.bsky.social
Hooked on watching the live cam of hummingbird feeders in the Ecuadorian rainforest! Hummingbirds hustle all day, and at night, the bats take the night shift. It’s like a 24-hour all-you-can-eat buffet! #Hummingbirds #Bats #Ecology #Rainforests

www.youtube.com/live/ie67zjk...
Two blue-green hummingbirds with white breasts are near three feeders—one in the middle, perching, and the other on the right side, hovering. A medium-sized bat is drinking nectar from the left side feeder, hovering for a second in front of the feeder.
February 3, 2025 at 4:35 AM
kazohashilab.bsky.social
Moir et al. (2025) asked how pollinators drive geographic floral divergence in Brunsvigia gregaria with a generalist pollination system. Style length correlates with the body length of locally important pollinators, highlighting their critical role in floral evolution. #Ecology

bit.ly/4aEqb8u
The title of the paper, 'A test of the Grant–Stebbins pollinator-shift model of floral evolution,' published in New Phytologist. Graphs showing how floral morphology in B. gregaria aligns with pollinator body size and contact probability. The first two graphs show that mean style length increases with pollinator body size (weighted mean pollinator body length and the mean body length of the most important pollinator group). The other two graphs show the probability of contact with floral reproductive parts by ubiquitous pollinators: honeybees contact them more often at short-style sites, while bee flies show no significant difference among sites.
January 31, 2025 at 1:38 PM
kazohashilab.bsky.social
If you see this quote with flowers from your gallery. We can all use some beauty right now (Hepatica nobilis var. japonica f. magna.)
Pink morph of Hepatica nobilis var. japonica f. magna. Pale pink morph of Hepatica nobilis var. japonica f. magna.
January 27, 2025 at 11:16 AM
kazohashilab.bsky.social
If you see this post, post or quote repost a swan or swans. #Waterbirds #Swans
Three white swans are about to land on the water.
January 26, 2025 at 11:02 AM
kazohashilab.bsky.social
The tundra swans (Cygnus columbianus) have returned to the pond for their midday nap after a busy morning of feeding. Never get tired of watching their dramatic water landings! #Waterbirds
Four white swans in flight, gracefully soaring through a soft blue and cloudy sky. A white swan gracefully descends toward the water, beak half open as if declaring, 'Here I aaaaamm!'
January 26, 2025 at 7:58 AM
kazohashilab.bsky.social
If you see this, quote with flowers from your gallery.
Purple Erythronium japonicum in bloom, set against a soft forest bokeh.
January 26, 2025 at 3:15 AM
kazohashilab.bsky.social
Just finished 'Silent Earth' by davegoulson.bsky.social! It’s easy to read, packed with fascinating insights, and perfect for everyone—even bug haters. Who knows? It might even change your mind about our six-legged friends. My only regret? Not picking it up sooner (but it's never too late)! #Ecology
Cover of Silent Earth by Dave Goulson: a dark background with colorful insects and plants arranged in a circle, highlighting the book’s focus on the insect apocalypse.
January 25, 2025 at 2:15 PM
kazohashilab.bsky.social
A Japanese clear-wing hawkmoth (Cephonodes hylas) rests on green leaves after hatching, its wings still covered with golden scales. #Teammoth
A hawkmoth with very green body and clear wings. Actually, the wings are still covered with golden scales bc it was just hatched.
January 24, 2025 at 11:55 PM
kazohashilab.bsky.social
Pollen from last-visited flowers gains a siring advantage by smothering or displacing earlier pollen on a pollinator's body. This reveals 'pre-mating' pollen competition and prompts considerations on the evolution of male reproductive strategies in flowers.
#Pollination #Ecology bit.ly/4h4joHD
The title of the paper: "Competition for pollen deposition space on pollinators generates last-male advantage". Pollen deposition probability and grain count in control and treatment trials. (i) Probability of deposition by male-phase flowers by sequence (1 = success, 0 = failure), and (ii) Number of grains deposited. Both panels show a second male advantage, likely from smothering/displacement or time effects. Time effects are unclear in (i) but suggested in (ii).
January 23, 2025 at 9:17 AM
kazohashilab.bsky.social
May 2025 bring countless wonderful moments, like swans soaring high into the #Bluesky!
January 1, 2025 at 12:45 PM
kazohashilab.bsky.social
I'm used to Henbit (Lamium amplexicaule) blooming, but wintersweet (Chimonanthus praecox) flowering this early surprises me. A fly (Stomorhina obsoleta) visits the flowers as well. 'Overwintering' locusts (Patanga japonica) are hopping around. This seems a warmer year-end than usual. #Ecology
Yellow flowers of wintersweet (Chimonanthus praecox). A fly (Stomorhina obsoleta) visits the flower, actively probing with its proboscis. A pair of red-purple flowers of henbit (Lamium amplexicaule). Overwintering locusts (Patanga japonica) holding onto grass.
December 28, 2024 at 5:09 AM