Winter is kind of sad, all my favorite photography subjects are either dead or dormant. But today it warmed up a bit and there was blue sky out so I found some beautiful subjects that are at their best in the winter, plants’ leaf buds! They are delightfully variable in shape and color among species, and many have quite a lot of character. Be sure to check leaf buds out next time you feel there is not much interesting out in nature to look at.
Cacti (family Cactaceae) are the strange and beautiful plants best known for inhabiting deserts and being a pain in your butt, hand, leg, or whatever body part that happens to brush up against them. These traits are the result of a fascinating evolutionary story that played out in the American deserts, at least initially.
So, cacti don’t have leaves, right? Well, kind of, but those spiky bits are technically modified leaves. That is why they are, in botanical lingo, spines. (Sharp plant parts derived from the epidermis are called prickles and modified branches or stems are called thorns). At some point early in the evolution of cacti their leaves evolved to be smaller and smaller and eventually into hardened points that did not photosynthesize. Cacti also evolved green stems which took over the photosynthetic tasks.
So why would cacti evolve these two unusual features of green stems and non-photosynthetic stabby leaves? Well, these combination of traits are adaptations to dry and resource-poor environments. Big and flat leaves have lots of surface area which is typically a good thing from a plant’s perspective as it captures lots of sunlight for photosynthesis. But many plants have more sunlight than they can handle and more photosynthetic area means more water loss. All photosynthesis requires gas exchange, carbon dioxide in and oxygen and water vapor out. So for plants in water-limited and very sunny environments, like deserts, adaptations that limit photosynthetic area (and thus limit water-losing gas exchange) are likely to be advantageous and selected for.
So as adaptation to very dry desert environments cacti evolved photosynthetic stems which presumably lessen water loss during photosynthesis. Great. But there are more photosynthetic tricks in cacti that you can’t see. Early cacti evolved an additional solution to the photosynthesis-water-loss problem, a whole new physiological mechanisms for photosynthesis called CAM photosynthesis. There are a lot of differences between CAM photosynthesis and what most other plants use, but the most important part is that cacti, and other CAM plants, can leave their stomata (the little pores that allow gas exchange) closed during the heat of the day and instead do all their gas exchange at night when it is cooler and more humid. This little trick greatly reduced water loss and gives CAM photosynthesis plants an advantage in very dry environments.
So why the spines? Why not just lose the leaves all together? The short answer is that spines are a defense against herbivores. Herbivory, or the consumption of plant matter, can be really bad news for a plant: get a bunch of your photosynthetic tissue eaten, have to grow it back, not enough resources left to produce seeds and reproduce, less offspring, lower fitness. Plants that get less damage from herbivores might have higher fitness so evolution should favor plants with traits that reduce herbivory. This is particularly true in environments where resources are scarce, like deserts, where regrowing tissue lost to herbivory is very difficult (this is called the Resource Availability Hypothesis). Thus, plants in low resource environments, like cacti in deserts, invest very heavily in defenses, like big gnarly spines.
The >1500 cactus species all live in the Americas (well except one in Africa, probably dispersed there by birds) and mostly in arid environments. However, there are also many cacti that live in the tropical rainforests of Central and South America. At first this doesn’t make sense why a arid-adapted group would have a center of diversity in some of the world’s wettest habitats, until you look at the micro-habitats they live in, namely, up in the forest canopy. Rainforest cacti are almost all ephiphytes, meaning they grow on other plants, normally the branches of large trees. From plants’ perspective these environments are actually very dry, it is hot, there is no soil to hold water, and airflow from all directions desiccates. So the elegant adaptation that cacti evolved in the deserts gave them an advantage as tropical ephiphytes and when they arrived in these new habitats they thrived and diversified.
Around 30 million years cacti emerged and in the last 10 million years spread across North and South America. This is amazingly fast for the evolution and spread of a plant lineage across such a large geographic area with a huge range of ecological conditions. This incredible success was likely due to the evolution of the morphological, physiological, and defensive traits that make cacti so unique and fascinating. Understanding their evolution requires thinking about the environmental and ecological conditions that cacti live and thrive in, and also remembering that those spines are not just a pain in your butt but also a pain in the butt (or mouth!) of anything that wants to eat them.
(All photos from the Sonoran Desert in Arizona)
This is a chronological romp through some of my favorite photos from the year with a little bit of narration as to what I’ve been up to. If you like what you see follow me on this blog or on twitter and flickr.
During a lab retreat in Algonquin Park we found these amazing insects that walk around on the snow! Quite an astonishing feat for a cold-blooded animal, more info here.
This is a Zoroptera, a rare order of insects with only 39 species. A great post about this species here.
Twin-spot skipper (Oligoria maculata).
Back in Ontario I got to work finishing up my thesis and applying for postdoc positions.
I still took time to get some insect photos though, here is a thistle bud weevil (Larinus planus) that my roommate brought to me. This individual had a very predictable behavior of walking up to the highest point, looking around and then flying off which made getting this shot possible, although it still required lots of persistence and patience.
The day after turning in my thesis I headed down to South Carolina to work in the field on the project I am currently working on as a postdoc. Some shots from South Carolina:
An unidentified juvenile jumping spider. This photo was one of my first serious attempts at photo stacking, this is actually a composite of 11 photos all merged together which gives greater depth of field to the image.
Buckeye butterfly (Junonia coenia) which escaped a bird attack, see the beak shaped hole in the right wing?
Leafhopper (Oncometopia sp.) from South Carolina. This is a stack of 13 images.
I headed back to Ontario where I successfully defended my PhD thesis, yaay! After that I went to a conference in Sacramento where I attended a field trip to Lake Tahoe (some pics here here here) and after that visited friends and family in Seattle and did nifty things like blueberry picking and playing a Horse Grinder show.
Back in Ontario: Walking through High Park in downtown Toronto with a friend I found a cicada just after emerging from the soil and watched it molt into its adult form. More photos here. Ant tending aphids in Mississauga, Ontario.
This is not a wasp.
In September I packed up and moved to East Lansing, Michigan, to start my new position at Michigan State University.
Lake Michigan shore. There were some wicked sand dunes nearby where I made a Horse Grinder music video.
Some beetles trying to hide from the cold winds along the lakeshore. Kinda like Abbey Road eh?
Tiger beetle, stack of 11 photos.
Over the holidays I traveled to Arizona to visit family: Tonto Natural Bridge.
Estrella Mountains near Phoenix.
Desert adapted fern found near Prescott.
I took a weekend trip out the Lake Michigan coast north of Muskegon, Michigan. As always, I was looking for arthropods to photograph but I had low hopes for finding any given the chilly weather.
But to my surprise I started noticing lady beetles perched on the beach grasses.
Then on the grasses closest to the water I found clusters of lady beetles sheltering from the wind.
Kind of like nature’s answer to Abbey Road eh? :)
Multicolored asian lady beetles are common predators of aphids in agricultural fields. After leaving the fields they were probably being blown around the lake desperately looking for somewhere to overwinter. In some places though it looked like the beach is where beetles go to die.
#IAmANaturalist. It’s only in the last year or so that I’ve become comfortable with using that title. More officially, I am an ecologist. Certainly these titles are not, and should not, be mutually exclusive. Actually, I think being both an ecologist and a naturalist is ideal as interests and insights in one are often inexorably linked to the other. However, up to this point, much of my research in ecology and evolutionary biology has not been particularly inspired or rooted in natural history observations, at least not my own observations. This is not necessarily a flaw, but rather something I would simply prefer not to be the case. Something to strive for in the future.
I mention this because natural history in the broad sense—attentive focus given to organisms, patterns, and processes in nature—has grown as a personal pastime and passion. This of course can take many forms: photographing arthropods, bird watching, walking through and enjoying natural landscapes, and identifying plants growing out of sidewalk cracks, just to name a few. My increasing comfort in calling myself a naturalist comes primarily from four realizations: 1) natural history observations are key in informing and inspiring interesting research questions in ecology and evolutionary biology, 2) basic natural history is of critical importance in managing species, communities, and ecosystem imperiled by anthropogenic changes (e.g. climate change, habitat destruction), 3) natural history is the common thread in basically all my interests and pursuits in life, 4) understanding of, and connection with organisms and natural places is simply very pleasing and can even evoke a sense of spirituality that is otherwise foreign to me.
Yesterday I headed up to Hartwick Pines State Park about two hours north of East Lansing, Michigan (where I just moved). I learned of this park from this list of old-growth forests. I knew visiting an old-growth forest in Michigan would help me gain a sense of place in this new environment.
The forest was a mix of white and red pine, sugar maple, beech, and eastern hemlock. The tall and straight white pines were the signature feature though, as they were typically larger in diameter and extended above the canopy of the other species. This 30 second video gives a sense of the environment better than anything I could write (do you hear the woodpeckers foraging?):
It is important to stop moving. Listen. Look. Smell. Touch. Taste. Tuning your senses to a natural environment always results in interesting discoveries. I was inspired to capture my discoveries with a poem (of sorts):
In these ancient woods
My eyes scan
For dead trees
I walk slowly
Peering around snags
Tail feathers pressed firmly against bark
Pounding fits of 8th notes
Head angled left
Chiseling bark and wood
Scatter and fall
On twigs and pine needles
Red squirrel shouts
Feverishly runs off
And then a duo
Both hopping upwards
White pine dance floor
For their performance
Of course there were other interesting sightings too:
Experiencing this setting, all the details, the clean smell of the air, even the mosquitoes that swarmed around me, was an uplifting experience. But it was also bittersweet. Undisturbed communities such as this old-growth forest are very rare. Building a connection with this unique place, this islands of unlogged forest, gave me the visceral realization that I was within a biome that is severely damaged, and in its pristine state, nearly extinct. Old-growth forests in North America are miniscule polka dots on a map dominated by landscapes fully or partially run over by humans’ destruction. Aldo Leopold said “One of the penalties of an ecological education is that one lives alone in a world of wounds.” This is the dark side of being a naturalist.
But there is power in connection with nature and power in feeling the pain of the gaping wounds ripped across our landscapes. Reed Noss said in his great book on the natural history of Southern Grasslands “Endless fascination with nature–nothing more and nothing less–is the key to enlisting people in the fight to save biodiversity”. If we can’t get more people to have personal connections with places and organisms then are attempts at protecting and rebuilding populations, communities, and ecosystems are doomed. This is another very important reason to be a naturalist, to identify as a naturalist, and to promote and share the practice of natural history.
We must remember that aboriginal cultures did not have a word for “nature” because they had no reason to consider themselves as separate from the world around them. Their lives were entirely dependent on their understanding of the organisms, communities, and ecosystems that surrounded them. This remains true today although it can be hard to tell and easy to forget. That understanding is scattered across our vast populations with selected few having the personal connections with the physical, chemical, and biological processes that allow our modern lives to continue as they do. When we become disconnected we lose wisdom, compassion, and foresight. Natural history is about rebuilding those connections. #IAmANaturalist, and proud of it!
This is a fly that is a very convincing wasp mimic, an example of batesian mimicry. Notice that it is covered in pollen so it must be visiting flowers. I spotted this today on a tree trunk at Erindale Park in Mississauga, Ontario, Canada.
A watchful eye and patience turn every nature walk into a fascinating spectacle.
I was walking with a friend in downtown Toronto’s High Park, checking out the birds and flowering plants, and looking at the insects on milkweed and goldenrod. Also, watching at all the dogs running around was pretty entertaining too. Throughout, I was trying to find a sugar maple to demonstrate how to distinguish them from the invasive norway maples that covered the park. For an hour or so I failed to find any, which was actually a bit sad. This is the symbol of Canada and they are being replaced by an invader!
Thankfully, there are still sugar maples in the park though, and I got excited when we finally found a grove of them. And before I could proceed with showing the differences between the two maples we spotted a cicada (a dog-day cicada, Tibicen canicularis) about 1 meter up the tree trunk that had just starting to molt. It didn’t seem to be moving though, and my first impression was that it had died in the process of molting–molting is a rough time in an insect’s life ya know. Lucky for out us, it was just fine, and with some patience we observed the full molting process (click image to view large):
Once the cicada broke free of its larval shell the wings unfolded and inflated with hemolymph (insect blood), turning from little shriveled green nubs to beautiful sets of wings. What a delightful and fascinating performance!
This species feeds on the roots of trees for several years than crawls out of the soil to transform into their adult form, mate, and lay eggs that will hatch and return to the soil. We were thrilled to experience this delicate and vulnerable moment in its life cycle.