Showing posts with label pollination. Show all posts
Showing posts with label pollination. Show all posts

Wednesday, September 27, 2017

Cheating in mutualisms? Nectar-robbing and nectar-thieving

As a pollination ecologist, I study the mutualistic relationship between plants and their pollinators. Mutualism is roughly defined as an interaction between organisms in which both partners benefit in some way. Pollination is often treated as a classic case: the pollinator gets nectar (i.e., food), and the plant gets pollination (i.e., reproduction).

However, it's worth remembering that neither participant is engaging in the interaction for the benefit of the other: in broad terms, the plant doesn't offer nectar to help out the pollinators, it does it because offering nectar improves the plant's success; the pollinator doesn't pollinate in order to help out the plants, it does it because foraging for food in flowers improves the pollinator's success. I've talked about plants that are jerks a few times before (1, 2, 3); today I'm going to talk about the flip-side of that, the 'pollinators' who are jerks. In this case, when I say that a plant or a pollinator is a "jerk", I mean that it has developed an adaptation that allows it to gain the benefits of the plant-insect interaction without offering the interaction partner any benefit -- in other words, it's a cheater. Deceptive plants fall under this umbrella, because they deceive pollinators by seeming to offer a reward, but without actually doing so and thus without incurring the cost of making the reward (usually nectar). There's some really cool research that has been done on the evolution of cheating in mutualistic relationships, which I may talk about another time. For today, I'm going to focus more narrowly on floral larceny.

So what is floral larceny? The general idea is that the putative pollinator is obtaining the reward without offering the service. So a floral visitor gets nectar without moving any pollen. Nectar-robbing is a frequently-studied form of floral larceny: the visitor, rather than trying to get in through the regular opening of the flower, just cuts a hole near the nectary and sucks up the nectar, avoiding contact with the reproductive parts of the flower and consequently providing no pollination service. In principle, certain floral shapes are adaptations that exclude bad pollinators and improve the fit of good ones by orienting them in particular ways in the flowers, but at least some of these flowers, particularly with long, tubular flowers, and especially the more rewarding ones, are more likely to be the targets of nectar robbers (Rojas-Nossa et al. 2016), so the extent to which they're actually excluding bad pollinators, as opposed to converting them into nectar robbers (which might be worse? Or not, see below), is unknown. Actual measured consequences of floral larceny on floral fitness actually range from negative to positive, which further complicates interpretation of nectar-robbing behaviour (see Irwin et al. 2010 Annual Reviews of Ecology, Evolution, and Systematics).

I managed to get some footage of a nectar robber on Impatiens capensis (jewel-weed). You can see that the robber bites a hole in the flower to get at the nectar; it's quite clear that the nectar-robbing wasp is bypassing the reproductive parts of this flower, but I witnessed several wasps engage both in nectar-robbing, and then in the more standard foraging that involved entering the flower and possibly transporting pollen. 



Similarly, if you look at the Xylocopa virginica (carpenter bee, notably one of the largest insect pollinators in this region; there are several shown in the videos below) on the hostas in the video below, first you can really clearly see in the slow-motion video as she pushes her tongue through the flower into the nectary, but in the next video in real-time, you can see that in some instances she may be brushing her very large abdomen over the reproductive parts of the plants anyway, and you can actually see some pollen grains on her shiny abdomen as she engages in this nectar-robbing behaviour, so it's not really clear whether she's truly failing to provide pollination services here, even while she engages in fairly classic nectar-robbing.





Another form of floral larceny is nectar thievery: the visitor enters through the normal floral opening, but does not make contact with the reproductive parts of the flower and consequently transfers no pollen. 

I have some footage of visitors engaging in nectar thievery on the hostas in my back yard. The video shows a relatively classical case, where the nectar thievery arises because of a morphological mismatch (i.e., the shape of the insect and flower don't match up correctly);this nectar thief is just too small to contact the reproductive parts of the flower, but of course that doesn't prevent it from foraging for nectar on the flowers.



There are also forms of floral larceny relating to pollen-robbing (which causes damage in the course of pollen removal, and in which the pollen isn't transmitted elsewhere), and pollen-thieving (no damage, but pollen is not transferred). There is very little information on these phenomena, probably because they would probably be extremely hard to confirm. Unfortunately, I don't have any footage of these. Pollen-thieving in particular might actually be quite common, depending on how we define it: here's some footage of X. virginica (carpenter bee) grooming pollen off herself; grooming is a common bee behaviour. Bees collect pollen to stock their nest cells with it (i.e., it's food for developing larvae), so a large quantity of the pollen they collect ends up not on other flowers but instead in the bees' nests. This might be considered a form of pollen theft, depending on how you want to define it. Pollen thieving is a rather understudied area, but there's an interesting review for those interested (Hargreaves et al. 2009).



Bonus, partial answer to one of the questions I raised in my first post about I. capensis (why are they shaped like this), here's Apis mellifera (honeybee) grooming herself after visiting I. capensis. Notice that the big patch of pollen between her wings isn't getting removed. Possibly, then, the shape of I. capensis helps to ensure that pollen is deposited on a part of the pollinator where it's less likely to get groomed off and therefore lost as food for bee larvae. The shape could also be at least partially driven by improved accuracy of pollen deposition onto stigmas; if the pollen ends up just anywhere on the pollinator, it might not be very accurately transmitted onto the stigmas of other flowers.



For fun, here's some footage of a Bombus sp. (bumblebee) worker who is definitely picking up pollen as she goes, though it's less obvious whether she's successfully depositing it on stigmas. Look at all that pollen on her abdomen! Pretty much whenever she enters and leaves the flower, she's brushing right up against the reproductive parts of the hosta:


Tuesday, September 19, 2017

Impatiens capensis pollination (Bonus: even bees can be clumsy)

I know I haven't blogged in quite a while. Life got very hectic for a while. In the months my last post, I have finished my M.Sc., gotten published, and moved to the University of Toronto to start my Ph.D.!

Over the weekend I got a chance to take a long walk with my patient and long-suffering husband, who indulged my snagging his new blackberry to take a ton of footage of bees visiting the tens of thousands (at least!) of Impatiens capensis (common name jewel-weed) in the ravine park near our new home. I made all sorts of exciting videos, but today I'm going to share just a few simple ones, as the others will take quite a bit of research and time to write up. I will post these throughout the fall because they're very exciting.

NOTE: I have been informed that my videos don't work on mobile. I'm working on it, but in the meantime they do run on desktop.
UPDATE: try clicking the title of the video instead (treat as link) on mobile. Opens in youtube app. If you don't have youtube app, please report back telling me what it does when you click the video link!

To start, here's a picture of the plant itself:

Impatiens capensis whole plant view

Let's take a quick look at some general reproductive biology of I. capensis. The plant is monoecious, meaning that each plant reproduces through both male and female function; however, each individual flower is unisexual (i.e., any given flower is either male or female but not both). In the photo below, I show three flowers on the same individual. If you look at the top of the "mouth" of each of the lower two flowers in the picture, you will see that each has a different structure; the middle flower has a large, bulbous, whitish structure, while the rightmost flower has a slender green structure.

Impatiens capensis male (middle) and female (right) flower
The middle flower is a male flower; the whitish deposit on it is pollen, ready to be deposited on the back of a pollinator that climbs into the flower looking for nectar (the nectar is in the nectar spur, the little narrow tube curling off the back of the flower, visible on the middle flower). The rightmost flower is a female flower, with a stigma ready to pick up pollen from the back of a visiting insect.

The flower has some rather complex floral anatomy I won't get into right now. There's a pretty good explanation of which parts are sepals and which parts are petals here for those interested. The important thing to note is the lower lip, made of two structures wrapping around the front of the flower, one on each side, that form a sort of landing area of pollinators. They also restrict the width of the flower opening (see photos below).

Impatiens capensis male flower front view. Note that the two sides of the "landing" petals on the front are not fused, just overlapping, and that their shape, because they come down from above around the opening of the cone, reduces the size of the entrance into the flower

Impatiens capensis male flower side view. Notice that the lower "landing" petals are not attached to the conical structure behind.

So I'm going to skip over all sorts of exciting stuff about this plant (why does it have unisexual flowers? Why place pollen on a visitor's back? What's up with that super-complex floral shape?) in order to move straight to some awesome video of assorted Hymenopterans (bees, wasps, ants) visiting this awesome flower!

So I noted above that the '"landing" petals form not just a place for a pollinator to land on the flower, but also a constriction around the opening of the conical part; remember that the nectar is all the way at the back of that cone, in the little nectar spur curling down under the flower. There are several strategies to get past the opening to access this nectar (and then leave again after): one is to simply be small enough to fit through the constriction made by the landing petals; that's how Apis mellifera (honeybee) is doing it (note at 10:00 that you can really see the pollen on this honey bee's back!):



Backing out of the flower can be quite tricky. I managed to get some footage of a visiting wasp finding an alternate method of exiting, which capitalises on the fact that the landing platform and the conical structure behind are not attached to each other:



The Bombus sp. (bumblebee) workers I saw visiting the plants, however, were too big to fit through the opening. But, have no fear! They worked it out anyway. Here's one worker diligently visiting lots of flowers. She's making more room for herself by using her strong back legs (2 pairs) to push the landing petals apart a bit, so that she can shove her head and thorax into the flower and get at the nectar. You'll notice that she doesn't have much difficulty leaving, either, since she's well placed with four legs outside the flower. As far as I can tell, she's just dropping right out of the flower and then flying away.




Here's a longer video of the same bee, diligently visiting a lot of flowers in a row. There's also a little bonus at the end of this video. If you've been clumsy and felt ridiculous for it recently, I have something to comfort you: even bees can be clumsy. If you watch closely at the end, you'll see her climb into a flower, and then she and the flower both fall off the plant to the ground!

Monday, July 20, 2015

Native Plants for the Pollinator-Conscious Gardener, Part 1: Blue vervain - Verbena hastata - Verveine hastée

The vervains (Verbena spp.) have started blooming in the wooded part of the Notre-Dame-des-Neiges cemetery. They are quite beautiful and where I was, they were absolutely teeming with a wide assortment of pollinators including bees, syrphid flies, skippers, and butterflies. Most of the shots I took actually were photobombed by a variety of pollinators!

Today, I would like to talk about Verbena hastata (blue vervain, fr verveine hastée). This beautiful flower is native to North America (US range map here, Canada range map here). It is listed as potentially weedy/invasive in the US [1], which, within its native range, means that it is a strong competitor and may squeeze out other plants under some conditions. This plant is secure in most of its native range [1,2], with the exception of British Columbia and Saskatchewan, where it may be at risk [2].

Verbena hastata inflorescence
This gorgeous flower can get pretty tall, anywhere from 2 to 5 feet [3,4,5,6]. It prefers moist soils [3,4,5,6] but there were lots of them growing at the top of the mountain, on the slope, and that is hardly a moist location so I would say it can prosper elsewhere. Verbena hastata has a solid upright form, as seen here:

Verbena hastata - full plant view
Verbena hastata is a member of the genus Verbena (vervains), a family with a long history of medicinal use. Verbena officinalis, the common vervain, is a popular garden plant possibly for its particular history in Europe as a medicinal plant [7], but Verbena officinalis is not native to North America [8]. The vervains are used medicinally to treat a number of ailments. Verbena hastata specifically, has been used to treat depression, fever, coughs, cramps, headaches, and jaundice [3,6,7]. There is, however, currently insufficient scientific evidence to back up the use of vervains to treat most of the ailments associated with them [9]. Please note that Verbena hastata is known to interfere with blood pressure medication and hormone therapy, and that in large doses can cause vomiting and diarrhea [3,6]. Do not consume this plant in any form if you are taking medications it could interfere with, and do not consume it in large doses.

Verbena hastata inflorescence

Verbena hastata is very attractive to a wide range of pollinators, including long-tongued bees, short-tongued bees, cuckoo bees, miner bees, halictid bees, and the verbena bee (specialized to Verbena spp.), as well as wasps, syrphid flies, true flies, beetles, butterflies, skippers, and moths [3,4,5,6]. At this point you may have noticed that I have listed essentially the entire range of insect pollinators. The plant also serves as a larval host for the common buckeye butterfly and feeds the caterpillars of verbena moth [3,5,6]. As a bonus, Verbena hastata is also attractive to some birds, for its seeds: cardinal, swamp sparrow, field sparrow, song sparrow, and the slate-coloured junco [3,5].

So if you are considering planting vervain in your garden, please consider taking this lovely native alternative to the more commonly selected Verbena officinalis. After all, the native Verbena hastata is beautiful, makes a decent tea (with the caveat about dose size and medical contraindications firmly in mind), and is great for the pollinators!

Monday, July 13, 2015

Wasps: Not Just Flying Agents of Pain

One of the things I encounter a lot when I talk to people about pollination is an intense fear of bees, and most especially of wasps. But wasps don't just sting you (and most won't sting without provocation); they also are pollinators. While on holiday at the lake, I captured a great series of a wasp worker hanging out on Achillea millefolium.

Unknown species of wasp on Achillea millefolium
Wasps are generally less hairy/fuzzy than bees, so they don't carry pollen as efficiently. But less efficient pollination != no pollination. Indeed, wasps are important pollinators in many ecosystems.

Another possible reason that wasps aren't such efficient pollinators of bees is that they don't (for the most part) rely solely on flowers for food. This individual actually may have inadvertently provided pollination services to the flower, but wasn't there collecting either nectar or pollen. She was dining on something else entirely:

A wasp eating something - note the ball of wax-yellow stuff
So I wondered what in the world she was eating. I looked from the front angle, hoping another angle might illuminate the matter:

Wasp eating something -- ball of stuff still unidentifiable
Nope, that was no help. Still a generally formless lump of gunk.

A quick glance around the environs, however, provided the answer:

Seems like a colour match for that wasp's meal
This dead grasshopper was on the stem of the flower where I found the wasp, and judging by the colour match and the big old hole in the dead grasshopper's abdomen, I suspect that the wasp found herself a rich source of protein and was taking advantage.

I suppose one animal's rather grisly find is another's feast.

Anyway, wasps will seek out other sources of protein (often to feed their young), including other insects, whereas bees generally don't. This reduced reliance on flowers may make them less likely to do the systematic flower-by-flower collection that also makes bees such suitable pollinators for flowers.

Wasps are actually an excellent biological control agent, as many of them have preferred prey which are pest insects on crops. I encourage them in my own garden because they're so efficient at getting rid of unwanted insects.

These oft-maligned insects are actually pretty awesome -- as long as you don't swat them or approach their nests late in the season.

Wednesday, July 1, 2015

Syrphid Flies - Syrphidae

I have mentioned syrphid flies before on my blog, usually when mentioning the pollinators of a given plant. But what's a syrphid fly?

"Syrphid fly" refers to an entire family of insects, the Syrphidae, which are bee and wasp mimics. They resemble bees or wasps, which confers some of the natural defenses and safety that would be accorded those more dangerous species that they emulate.

Many syrphid flies are nectar and pollen eaters, and so will be attracted to flowers and provide pollination services. Many of these species are not nectar-robbers but pollinators, though we don't necessarily think first of flies when we think of pollinators.

This family is quite large and diverse. I am not, for the most part, able to identify particular species of syrphid fly. Sometimes it is obvious that two individuals belong to different species; other times, it takes close observation.

There were quite a lot of syrphid flies visiting the flowers of the insect gardens in the Montreal Botanical Gardens. They were mostly of the same size and shape, so probably the same genus. It wasn't until later when I was looking at my photographs that I realized that there were multiple species. Take this one here:

Syrphid fly
 This one has dark eyes, and a stripey abdomen which transitions from yellow to red at the tip.

Syrphid fly
This second one (I posted this photo yesterday for the discussion of Rudbeckia hirta), on the other hand, has red eyes, and a yellow patterned abdomen.

Likely these are two different species (I say likely because I am not certain of this; it is theoretically possible that there might be extreme polymorphism in a single species, but unlikely).

As I was looking through the photos another thing jumped out at me. In that first photo, the syrphid has a strange, bulgy yellow protuberance between its eyes. I wondered what it was: mouth parts? A sensory organ of some sort?

So I trotted down to reddit and asked the helpful entomologists on /r/whatsthisbug about it. I was told that that yellow protuberance is actually the antennae, which are frequently heavily modified in syrphid flies. So. Syrphids can have very strange-looking antennae indeed.

Saturday, May 30, 2015

Lepidopteran Pollinators & the Proboscis

So I've talked about various types of bee pollinator, fly pollinators, and even wind. But I haven't talked much about Lepidopterans (butterflies).

Today, while out enjoying the weather in the wooded portion of the Notre-Dame-des-Neiges cemetery, I encountered a couple of common butterflies that, unusually, held still long enough for me to photograph them, so I'm going to take my opportunity to talk a little bit about this group of pollinators.

First up, we have the very common Glaucopsyche lygdamus couperi ('Silvery Blue' butterfly), a native of North America with a fairly broad range [1] which you have probably seen before:

Glaucopsyche lygdamus couperi - this individual very obligingly held still for me so I could get a few photos
 Lepidopterans tend to be nectar-feeders, so plants that have co-evolutionary relationships with them will generally produce it in reasonable quantity. They are not as efficient at pollen transfer as bees, as their bodies tend to be lifted up on long legs that prevent the extensive physical contact that we often observe between bee and stamen. Nevertheless, they are valuable and effective pollinators.

Glaucopsyche lygdamus couperi on Vicia cracca (cow vetch) - this is what the underside of the wings looks like
Lepidopterans have one piece of handy equipment that other pollinators do not: a proboscis. The proboscis is a tubular mouthpart that serves essentially as a straw. It varies in length depending on species and, in the case of the longer ones, can be extended or coiled as needed.

So if you're a plant that would benefit from attracting butterflies and excluding other pollinators (perhaps in order to devote your resources to a single, more loyal species rather than take your chances with more fickle visitors), what kind of structure is most suitable? A deep nectar spur (pocket where nectar is produced and stored) that can only be accessed with an insecty straw, of course! So the more exclusively Lepidopteran-pollinated a species, the more likely it is to have a long nectar spur which can only be accessed via proboscis.

I got a fantastic shot of the very common Poanes hobomok ('hobomok skipper' butterfly) using its proboscis to suck up some nectar from Vicia cracca (cow vetch):

Poanes hobomok collecting nectar from Vicia cracca
Poanes hobomok, like G. lygdamus couperi, is native to this region and also very common [2], so it's very likely you've seen one of these before.

Of course, Lepidopterans can and do get nectar from a variety of flowers, many of which aren't specialized exclusively to them, such as Vicia cracca (cow vetch). This introduced species is originally native to Europe which is now broadly distributed in North America (range map here). It is listed as invasive but with low current threat status in Minnesota [3]. Apparently the spread of this species is also leading to a range expansion for the native Lepidopteran G. lygdamus couperi [1].

Vicia cracca
The peas produced by this plant are edible [4] though in my experience not that tasty (starchy, bland).

Vicia cracca
The USDA forest service has a little blurb page about butterfly pollination for those interested. And, a bonus picture:

Poanes hobomok on Vicia cracca

Thursday, May 29, 2014

Marsh Marigold - Caltha palustris - Populage des marais

During my time at QUBS, I did some (undergraduate, short-term, for a field course) research on Caltha palustris (marsh marigold, fr: populage des marais), family Ranunculaceae. It was a remarkably profuse bloomer and appears to be a pollinator generalist - it was pollinated by just about any insect which pollinates flowers, including bees (mostly Apis mellifera), bumble bees (Bombus spp.), solitary bees (diverse groups from Hymenoptera), syrphid flies (Syrphidae), true flies (Diptera), beetles (Coleoptera), and ants* (Formicidae). There were also some moths & butterflies around (Lepidoptera) but following our observation paradigm, my colleague and I witnessed no instances of these pollinators visiting the flowers - most likely just because they were so rare that it would have taken considerably more observer effort to see the Lepidopterans visiting C. palustris. There was no indication that birds pollinate C. palustris and I have no idea if bats visit the flowers (unlikely, as flowers which are specialized to attract insects tend not to have the various specializations which would attract birds or bats).

C. palustris
Solitary bee on C. palustris
C. palustris' conservation status is unranked but considering that it grows in wetlands (an increasingly threatened ecosystem), one should presumably treat the plant with caution. It certainly appeared in remarkable profusion at our study site, so we did not take extraordinary measures to safeguard it against our movement through the marsh etc, but I cannot speak for other sites. A good rule of thumb is to damage as little as possible regardless of the conservation status of an organism.

C. plaustris came rapidly into bloom at the test site and the flowers began to senesce within a few days. It is unclear whether the floral senescence was triggered by pollination (pollinators were remarkably abundant) or if the plant only ever sustains them for a few days.

C. palustris at the marsh - day 0 (project planning)

C. palustris at the marsh - day 1 (data collection)

Our study looked at the impact of floral outline (highly variable in this species) on pollinator behaviour. Tentatively, our results suggest that  the introduction of A. mellifera may end up altering the phenotype distribution in this population, as the A. mellifera showed a statistically significant preference for floral morph where the native pollinators do not. This has widespread implications for plant populations in North America -- however, we should take these results with a huge grain of salt because the data was collected by two undergrads in three days and the stats were an overnight affair.

Research photo used to quantify floral outline variation
As above
As above

I actually enjoyed sloshing about in the marsh, even when I was wet and muddy and losing my rubber boots to the mucky depths.Somehow, the tedium of watching bees land on flowers all day in the muck was quite agreeable to me.

*it is possible that the ants were not pollinating but rather stealing nectar, ie taking the pollinator reward without providing any pollen transfer for the flower; ants do pollinate some flowers but are mostly nectar-robbers. My colleague and I did not have a chance to establish with any certainty whether the ants were antagonists or mutualists with C. palustris.

C. palustris

Monday, July 8, 2013

Bumblebees - B. impatiens - Bourdons

So I suppose it's about time I talked about the garden a bit. This year, E and I are trying something new. Back in a post on July 5, 2012 (Pollination Station), I illustrated my method for ensuring pollination of some of the plants for which pollination is necessary for production. It involved running around with a brush, a decidedly inefficient and inelegant state of affairs. The garden I maintain is on three levels: ground level, second floor, and third floor. Pollinators are unfortunately quite rare on the third floor, presumably because bees well-laden with nectar and pollen don't have any interest in flying up two stories to look for more.

So this year we're trying something new. E is doing some bee research at a lab at the university, under the supervision of a researcher who has been invaluable in her assistance to get us started. Basically, we're raising a bumblebee colony. Bad. Ass.

... The process is surprisingly sensitive. We ran around with nets and pill bottles early in the season, capturing bumblebees (bombus impatiens), because early in the spring all the bumblebees are queens; the queen comes out of hibernation and flies around collecting pollen and nectar and looking for a suitable nest site, then eventually starts laying eggs. Actually, there's a rather low success rate for b. impatiens colonies, so it was necessary to capture multiple queens in hopes that one would reproduce, so I should say that only some of them eventually start laying eggs.

So. We caught some bees. Watched and waited. Finally, one of them appears to be incubating eggs. The rest have been released, and Gardenia (that's the name we gave the successful queen) has been moved outside and we've opened up the incubator for her in case she wants to forage. We've supplied her with nectar and pollen, as well as cotton to use in forming the initial nest, so she doesn't actually have to leave. Eventually her workers will leave the hive to forage. And then they will pollinate our garden goodies and I won't have to run around with a paintbrush anymore.

Peeking into the nest
 You'll notice right away while looking at the above shot that b. impatiens doesn't make the organized honeycomb that people generally expect when thinking of bees.

The incubator
 This is the exterior of the incubator. The closer portion is where the nest is; the further portion is where we're putting a capful of nectar for Gardenia, which prevents the need for her to venture outside in order to support the colony (the pollen we've provided her with is visible in the photo of the nest).

Location of the incubator
We've tucked the incubator into a quiet corner of the deck for now, with the exit facing directly into the planters where I've put some of the flowers I planted this year in order to supply the colony. We are anticipating the possibility that we'll have to provide them with nectar or pollen as the season wears on, but we'll be monitoring the colony closely.

We'll be moving the nest into its proper box soon so that the hive has the chance to grow and spread.

But of course, social bees aren't the only bees who pollinate the garden. Far from it; solitary bees (bees who do not form colonies, but rather forage & reproduce individually) are extremely common and also very important for pollination. Fortunately, keeping solitary bees is considerably less time-consuming and difficult than trying to establish a colony. Solitary bees just need to be provided with a suitable nest site, and they'll move right on in!

This is where my dad kicks ass. I was doing some research on solitary bees (I'm less familiar with them), and found out exactly how to set up for solitary bees. My father, once I explained the process to him, pulled out his drill bits and got some wood and helped me set up some solitary bee space.

I'm not really expecting to get any solitary bees this year (it's a little late for nesting), but at the very least we should get some next year. Since we have an apple tree in the back yard, that's to the good.

Close-up of part of the bee house
 Solitary bees are of varying sizes, so need tunnels of varying sizes to accommodate them. My dad drilled some holes of varying sizes on two sides of two of our fenceposts (total of four sides drilled). Solitary bees look for tunnels of the right size to nest in; holes in wood are appealing enough, so that's what we've put up here.

One of the bee houses from a distance
My dad then sheltered the bee houses, to keep the rain out (wetness prevents the bees from prospering).

So there we have it.  My dad rocks. So do bees.

Of course, this blog just wouldn't be what I've always envisioned it to be if I didn't take a moment to also share a photo of something I thought was particularly beautiful today. Enjoy.

Browallia speciosa

Calibrachoa