Blues (Not All of Them Blue) (Taxon of the Week: Polyommatus)

I'm heading into the field tomorrow for two weeks and won't be able to respond to comments on this post, so I'll just give you a light coverage for the latest Taxon of the Week, the butterfly genus Polyommatus:


Male of the blue butterfly Polyommatus escheri, a widespread species in Europe. Photo by Eric Sylvestre.

Polyommatus is a genus of about 200 species of butterfly found in Eurasia and northernmost Africa with the highest diversity seemingly around west central Asia from Turkey to Iran. It is divided into a number of subgenera (recognised as separate genera by some authors) with the largest, Agrodiaetus, including about 130 species (Wiemers et al. 2010). As the common name 'blue' would suggest, the males of most species are a brighter or paler shade of blue; females are generally brown.


Female of Polyommatus semiargus (or Cyaniris semiargus). Photo by James Lindsey.

The majority of Polyommatus species lay their eggs on plants of the family Leguminosae. Like many other species of the family Lycaenidae to which they belong, caterpillars of Polyommatus show an association with ants. In the species in which this association has been most studied, the common blue P. icarus, the association is facultative only; the caterpillars may reach maturity without ever being tended by ants (other lycaenid species may require tending to survive).


Female of Polyommatus agestis. Photo by Hans-Peter.

When the caterpillar of Polyommatus icarus reaches its fourth instar, it starts producing honeydew from an organ on its abdomen. It will also produce vibrations that travel through the ground and may attract ants. Arriving ants are presented by the caterpillar with honeydew, in return for which they tend the caterpillar and protect it from predators and parasitoids. The caterpillar also possesses a pair of eversible tentacles on either side of the honeydew organ that it displays when it registers the presence of ants; displaying the tentacles seems to encourage attention from the ants somehow, perhaps by releasing pheromones (Axén et al. 1996). When the caterpillar moults into a chrysalis, the ants bury it under a light covering of soil and leaf litter where it remains until the adult butterfly emerges after two weeks.


Polyommatus ainsae (or Agrodiaetus ainsae), an inhabitant of northern Spain. Photo by Teresa Farino.

REFERENCES

Axén, A. H., O. Leimar & V. Hoffman. 1996. Signalling in a mutualistic interaction. Animal Behaviour 52: 321-333.

Wiemers, M., B. V. Stradomsky & D. I. Vodalazhsky. 2010. A molecular phylogeny of Polyommatus s. str. and Plebicula based on mitochondrial COI and nuclear ITS2 sequences (Lepidoptera: Lycaenidae). European Journal of Entomology 107: 325-336.

Life in the Fast Lane (Taxon of the Week: Astigmata)

Amongst the bewildering diversity of mites inhabiting this world, the Astigmata include some of the most significance to humans. This group of 5000+ species (with doubtless many more waiting to be described) has become specialised for rapid development and high fecundity. Originally scavengers on decomposing organic matter, members of some lineages have become parasites on vertebrates.


Dust mites Dermatophagoides pteronyssinus on a bedsheet. Dust mites are common inhabitants of human houses where they feed on particles of organic matter such as flaked skin. For the majority of people, their presence in the house is of no consequence; an unfortunate minority suffer allergies to dust mite waste products. Photo from Time.

Curiously, the soft-bodied, fast-living astigmates are most closely related among other mites to the heavily-armoured, long-lived Oribatida. In fact, both morphological and molecular phylogenetic studies have indicated that astigmates are derived from within oribatids (though recovering this result in molecular analyses is dependent on the analytical method used due to the much faster evolutionary rate of astigmates; Dabert et al., 2010*). Astigmates have been derived from oribatids by a process of neoteny where the characters of nymphal oribatids have been carried over to the adult astigmate (OConnor, 2009). Astigmates have also developed a highly modified deutonymph (the second nymphal stage of development) that is specialised for dispersal through phoresy (hitching a lift on some flying insect). The astigmate deutonymph (referred to by many authors as a hypopus) is generally non-feeding and the well-developed mouthparts present in the earlier protonymph become rudimentary, only to reappear when the mite moults through to the next stage, the tritonymph. In many species, if conditions are favourable and dispersal unnecessary, a protonymph may moult directly into a tritonymph, bypassing the deutonymph stage. Other species will only develop into deutonymphs if a suitable host for dispersal is available. The Psoroptidia, the main vertebrate-associated lineage of astigmates, have dropped the deutonymph from their life cycle entirely.

*And a thank-you to Macromite for notifying me of this paper).


Deutonymphs of Chaetodactylus micheneri on a specimen of the bee Osmia californica. Though it may not look pretty, most phoretic organisms do not actually parasitise their hosts, only using them for transport. Photo from here.

While some phoretic astigmates will attach themselves to any old host, others may be very specialised. The members of the subfamily Ensliniellinae (family Winterschmidtiidae) associate solely with nest-building wasps and bees. The early stages of the enslinielline life cycle occur in the host's brood cell and the mites reaches their phoretic stage when the host larva has matured and is ready to leave the brood cell as an adult wasp (or bee). At that point, the mites cluster in specialised pockets on the host's body called acarinaria. In the wasp Ancistrocerus antilope, only the male wasps emerge from the cell carrying mites in acarinaria behind the wings (the females kill any mites in their brood cell while larvae); when the male mates with a female, its mite passengers abandon him to enter acarinaria around the female's genitalia (Houck & OConnor 2001). In other wasp species, the females carry mites in acarinaria from when they emerge. When the female lays its eggs, the mites leave the acarinaria to be sealed in the new brood cells where they will mate and lay their own eggs.


The scabies mite Sarcoptes scabiei. The Sarcoptidae are a family of parasitic mites that burrow into the skin of mammals. Most species are specialists on a small range of hosts, most commonly bats (for some reason, bats carry an extraordinary diversity of parasites), but S. scabiei is a generalist species that has been found on a wide range of hosts, from humans to wombats. Photo by Louis De Vos.

You might be wondering what the wasp gets out of this arrangement as it is hard to see why it would have developed specialised structures to transport the mites if it was not benefiting somehow. And yet, at best, the mites seem to have no significant effect on their hosts; at worst, they are actively harmful, feeding on the food stores left for the developing larva or on the larva itself (though no parasitic ensliniellines have been known to cause the death of their host). Klimov et al. (2007) have suggested that acarinaria have developed not to facilitate the mites' development but to contain them. The mites cannot break through the walls of the brood cells themselves; they can only be carried by an emerging host. If the mites cluster into acarinaria before the host emerges, they remain with already-infected individuals rather than spreading to their potentially mite-free siblings. Perhaps adaptation is not always a matter of achieving an optimum; perhaps it is sometimes simply a form of damage control.

REFERENCES

Dabert, M., W. Witalinski, A. Kazmierski, Z. Olszanowski & J. Dabert. 2010. Molecular phylogeny of acariform mites (Acari, Arachnida): strong conflict between phylogenetic signal and long-branch attraction artifacts. Molecular Phylogenetics and Evolution 56 (1): 222-241.

Houck, M. A., & B. M. OConnor. 1991. Ecological and evolutionary significance of phoresy in the Astigmata. Annual Review of Entomology 36: 611-636.

Klimov, P. B., S. B. Vinson & B. M. OConnor. 2007. Acarinaria in associations of apid bees (Hymenoptera) and chaetodactylid mites (Acari). Invertebrate Systematics 21 (2): 109-136.

OConnor, B. M. 2009. Cohort Astigmata. In: Krantz, G. W., & D. E. Walter (eds). A Manual of Acarology, 3rd ed., pp. 565-657. Texas Tech University Press.

Name the Bug # 18

Continuing with the developing theme of post previews, these creatures and their nearest and dearest will be the subject of Taxon of the Week tomorrow. What are they?



Attribution, as always, to follow.

Update: Identity now available here. Image from here.

A Simple Stream Life

In a footnote to a recent post, I made the offhand comment that the strangest flowering plants were to be found among the Podostemoideae. Today I'd like to introduce you to them.


Unidentified Podostemaceae (perhaps Podostemon) collected from a fast-flowing stream in Venezuela. Photo by Kevin Nixon. (And yes, this is the identity of Name the Bug #17.)

Podostemaceae is a family of about 270 species of freshwater aquatic plants found mostly in tropical parts of the world. The family is divided into three subfamilies, Podostemoideae, Tristichoideae and the monogeneric Weddellina. The main difference between Tristichoideae and Podostemoideae is that the flowers of the latter developed encased in a sack-like covering called a spathella. Weddellina resembles tristichoids in lacking a spathella but some of the finer features of its flower anatomy are more like podostemoids, to which phylogenetic analysis indicates it is the sister taxon (Kita & Kato 2001).

Podostems specialise in living in fast-moving, temporary streams and waterfalls that become dry for part of the year, usually on rocky surfaces. Many podostem species are known for having ridiculously small distributions, often restricted to a single waterway (more on that later). Podostems differ from all other aquatic flowering plants in lacking aerenchyma, the gas-filled tissue I mentioned in reference to duckweeds. The primary podostem morphology involves spreading, usually flattened 'roots' that give rise to branching 'shoots' that in turn produce 'leaves' (Rutishauser 1997). However, all parts are photosynthetic and these structures probably do not correspond directly to comparable structures in other plants. The plumule and the radicle, the initial shoots in a normal germinating seed that develop into the stem and the root, respectively, are absent in most podostems (Sehgal et al. 2002). Instead, the germinating plant body develops as a lateral outgrowth of the hypocotyl, the stem that would normally support the plumule. The plant attaches itself to the rock by small rootlets growing from the 'roots' or by disk-shaped holdfasts. Either the rootlets attach themselves in pre-existing films of adherent bacteria (Jäger-Zürn & Grubert 2000) or they may secrete their own sticky mucilage (Sehgal et al. 2002). In the Indian Dalzellia zeylanica the distinction between 'roots' and 'shoots' has disappeared entirely; instead, the plant grows as a crustose thallus bearing both rootlets and 'leaves'. 'Leaves' of podostems are varied in appearance from large compound structures up to two metres long to minute scales or bundles of filaments. Species with larger leaves often have hairs, prickles or warts covering their surface.


The South American podostem Rhyncholacis penicillata in flower. Photo by Berrucomons.

The flowers of podostems, whether covered by a spathella or not, are very variable. Inflorescences of Mourera fluviatilis (the species with the two-metre leaves) can be up to 64 cm tall including the spike with up to ninety flowers. Other species (including all Tristichoideae) may bear only a single flower on a short stem. Depending on the species, podostem flowers may be wind-pollinated, insect-pollinated or self-pollinated. Podostem seeds are tiny, wind-dispersed and lack endosperm (podostems lack the double fertilisation of most flowering plants). 1g of weight may contain over a million seeds. Fruits vary greatly in size between species - Mourera fluviatilis may produce fruits containing up to 2400 seeds each while Farmeria metzgerioides produces only two seeds per fruit. In the case of the latter, the fruit doesn't break open to release the seeds; instead, the seeds germinate in place over the remains of their parent.


Podostemon in the dry season: desiccated thalli holding maturing fruits. Photo by Renato Goldenberg.

Much speculation has been conducted on why so many podostems have restricted distributions. Some have implied that many podostem 'species' may turn out to be ecological variants of more widespread species; however, multiple podostem species may be found growing in a single habitat. Others have suggested that podostems are somehow under less selective pressure morphologically than terrestrial plants, allowing a higher rate of mutational drift; however, this proposal remains untested. Interestingly, the molecular phylogenetic analysis of Kita & Kato (2001) found that the highly modified Dalzellia zeylanica was closely related to the morphologically conservative Indotristicha ramosissima. Indeed, the genetic distance between the two was little greater than that between separate populations recognised as the single species Tristicha trifaria, unusual among podostems in being found in both Africa and the Americas. This would suggest that podostems are indeed capable of rapid morphological changes—the only question is how?

REFERENCES

Jäger-Zürn, I., & M. Grubert. 2000. Podostemaceae depend on sticky biofilms with respect to attachment to rocks in waterfalls. International Journal of Plant Sciences 161 (4): 599-607.

Kita, Y., & M. Kato. 2001. Infrafamilial phylogeny of the aquatic angiosperm Podostemaceae inferred from the nucleotide sequences of the matK gene. Plant Biology 3 (2): 156-163.

Rutishauser, R. 1997. Structural and developmental diversity in Podostemaceae (river-weeds). Aquatic Botany 57: 29-70.

Sehgal, A., M. Sethi & H. Y. Mohan Ram. 2002. Origin, structure, and interpretation of the thallus in Hydrobryopsis sessilis (Podostemaceae). International Journal of Plant Sciences 163 (6): 891-905.

If a Komokiacean Turns Up in a Phylogeny, Will Anybody Notice?

It's possible that only one reader will care about this. But this is one minor detail that I came across while researching yesterday's post.

Komokiacea are large deep-sea branching protists that are expected, but not conclusively demonstrated, to belong or be related to Foraminifera. Attempts to extract molecular data for komokiaceans have, to date, failed miserably (Lecroq et al., 2009). Or have they?

In a paper written by Gooday et al. (1997), my attention was caught by the offhand comment: "We include Rhizammina algaeformis Brady 1879 [another deep-sea branching foram] within the Komokiacea on the basis of its 'softpart' organization". This relationship, it turns out, had originally been proposed by Cartwright et al. (1989). If this assignment is correct then komokiaceans have been appearing in molecular phylogenies for some years and nobody has been paying a blind bit of notice! Even more interestingly, Pawlowski et al. (2003) placed Rhizammina as sister to the xenophyophore Syringammina. Xenophyophores resemble komokiaceans both in being large branchers and in the sequestration of stercomata (faecal pellets) within their structure. A close relationship between the two groups would be quite credible. However, no other authors to date appear to have commented on Cartwright et al.'s reclassification of Rhizammina so I have no idea whether it's regarded as credible.

Discuss.

REFERENCES

Cartwright, N. G., A. J. Gooday & A. R. Jones. 1989. The morphology, internal organization, and taxonomic position of Rhizammina algaeformis Brady, a large, agglutinated, deep-sea foraminifer. Journal of Foraminiferal Research 19 (2): 115-125.

Gooday, A. J., R. Shires & A. R. Jones. 1997. Large, deep-sea agglutinated Foraminifera; two differing kinds of organization and their possible ecological significance. Journal of Foraminiferal Research 27 (4): 278-291.

Lecroq, B., A. J. Gooday, T. Cedhagen, A. Sabbatini & J. Pawlowski. 2009. Molecular analyses reveal high levels of eukaryotic richness associated with enigmatic deep-sea protists (Komokiacea). Marine Biodiversity 39: 45-55.

Pawlowski, J., M. Holzmann, J. Fahrni & S. L. Richardson. 2003. Small subunit ribosomal DNA suggests that the xenophyophorean Syringammina corbicula is a foraminiferan. Journal of Eukaryotic Microbiology 50: 483-487.

Three Random Foram Genera (Taxon of the Week: Pelosininae)

In an earlier post, I introduced you to the agglutinated forams of the family 'Saccamminidae'. As explained in that post, 'Saccamminidae' is undoubtedly a polyphyletic assemblage of forams of very simple morphology. In the influential, and outdated, classification of Cushman (1940), 'saccamminids' were divided between four subfamilies for which odds are that each of those subfamilies are as polyphyletic as the whole. Let's take a look at the members of one of those subfamilies and see where they are now.


Pelosina variabilis. Photo by Jan Pawlowski.

The subfamily Pelosininae, as recognised by Cushman (1940), included the genera Pelosina, Technitella and Pilulina. The distinguishing characteristics of this subfamily were that its members had free, unattached tests with a single chamber, at least one aperture and walls composed of fine particles. All three also live in the deep sea and include relatively large species for forams (up to 60 mm in height in Pelosina). In the classification of Kaminksi (2004), none of these genera were closely associated. In the case of Pelosina, Cushman was not even correct about the few defining features of the subfamily because this genus does live attached to the sediment by root-like structures (Rützler & Richardson 1996). Pelosina species are one of a number of tree-like forams that form a significant component of the deep-sea benthic community.


Technitella legumen. Image from here.

Technitella, in contrast, is an elongate, somewhat sausage-like form. The name of the genus ("little workman") refers to its elegantly constructed test, constructed from carefully selected materials. Heron-Allen & Earland (1909) described one species, T. thompsoni, which uses nothing but brittle star plates while T. legumen prefers sponge spicules, arranged in two layers with the spicules in each layer at right angles to each other to strengthen the test. Heron-Allen and Earland mused that "Probably we should be considered as imposing too weighty a postulate upon the members of the Club if we ventured to suggest that these rudimentary organisms were gifted with any aesthetic sense... it would appear that this "primordial, protoplasmic, atomic globule" is by no means so elementary an organism as naturalists are inclined to believe".


Lectotype and paralectotype of Pilulina jeffreysii. Photo by Andrew Henderson.

Finally, Pilulina constructs a globular test of felted sponge spicules with an elongate aperture like the mouth on a stick-figure's face. Of the three genera, only Pelosina and Pilulina have appeared in molecular phylogenetic analyses and the two do not appear to be associated, sitting instead in separate parts of the saccamminid cloud (e.g., Lecroq et al., 2009). Mikhalevich & Voronova (1999) argued that Pelosina is in fact a xenophyophore and placed it in the order Stannomida with the genera Stannoma and Stannophyllum. This was based on the supposed presence of linellae, a structure only otherwise found in stannomids. No molecular analysis has indicated an association between Pelosina and other xenophyophores. However, no other stannomid has appeared in these analyses, so just because Pelosina is not directly related to xenophyophores may not necessarily mean that it is not directly related to stannomids.

REFERENCES

Cushman, J. A. 1940. Foraminifera: their classification and economic use, 3rd ed. Harvard University Press: Cambridge (Massachusetts).

Heron-Allen, E., & A. Earland. 1909. On a new species of Technitella from the North Sea, with some observations upon selective power as exercised by certain species of arenaceous Foraminifera. Journal of the Quekett Microscopical Club, second series 10: 403-412.

Kaminski, M. A. 2004. The Year 2000 classification of the agglutinated Foraminifera. In: Bubík, M. & M. A. Kaminski (eds) Proceedings of the Sixth International Workshop on Agglutinated Foraminifera. Grzybowski Foundation Special Publication 8: 237-255.

Lecroq, B., A. J. Gooday, T. Cedhagen, A. Sabbatini & J. Pawlowski. 2009. Molecular analyses reveal high levels of eukaryotic richness associated with enigmatic deep-sea protists (Komokiacea). Marine Biodiversity 39: 45-55.

Mikhalevich, V. I., & M. N. Voronova. 1999. O sistematicheskom polozhenii roda Pelosina (Xenophyophoria, Protista, inc. sedis). Zoologicheskii Zhurnal 78 (2): 133-141.

Rützler, K., & S. Richardson. 1996. The Caribbean spicule tree: a sponge-imitating foraminifer (Astrorhizidae). Bulletin de l'Institut Royal des Sciences Naturelles de Belgique 66 (Suppl.): 143-151.

Name the Bug # 17

Here's another one that's a preview for an upcoming post. Can anyone tell me what this is?



Attribution, as always, to follow.

Update: Identity now available here. Photo from here.

Acknowledgements

The process of shifting Catalogue of Organisms to Field of Science seems to be just about complete. The Search field at top right may be a little unreliable for the next few weeks but that will hopefully correct itself as Google rediscovers the older pages.

A massive thank-you must be extended to Edward Michaud who has been working behind the scenes to make this all happen. Certainly, your humble servant (who, technologically speaking, is still trying to find the right angle to strike the rocks together) would not have been capable of doing all this. Tah.

The Thalli that are Green (Taxon of the Week: Lemnoideae)

The Araceae is the family of plants including such widely-grown species such as calla lilies and taro. Among other things, the family is famous for including some of the largest floral structures in the world. What is perhaps less widely appreciated is that it also includes some of the smallest and also some of the strangest flowering plants of all*.

*The very strangest flowering plants are the Podostemoideae, but I'll save them for another day.


Wolffia arrhiza, one of the world's smallest flowering plants. Each separate dot is an individual plant. Photo by Christian Fischer.

Duckweeds are the minute plant that can be found growing in large numbers on many still bodies of water. The main body of the plant is a flattened, often oval thallus (not a leaf but rather a highly reduced and fused leaf and stem). In three of the recognised genera of duckweeds, Lemna, Spirodela and Landoltia (the 'Lemneae'), one or more short roots emerge from one end of the thallus (the proximal end). In the other two genera, Wolffia and Wolffiella (the Wolffieae), the thallus lack roots. The vascular system is greatly reduced in 'Lemneae' and almost entirely absent in Wolffieae. Much of the thallus is occupied by gas-filled spaces that keep it buoyant (Hillman, 1961). The proximal end of the thallus also bears pockets on the underside from which daughter thalli grow vegetatively or in which the flower develops. The 'Lemneae' possess two such pockets, one on each side, while the Wolffieae possess only a single pocket. The entire plant is generally less than five millimetres (the size reached by Landoltia punctata) while Wolffia individuals are less than half a millimetre long when mature. Phylogenetic analysis indicates that the 'Lemneae' are paraphyletic; Lemna, which is smaller than Spirodela and Landoltia with only a single rooth per thallus, is sister to the even more reduced Wolffieae (Les et al., 2002).


Spirodela (large thalli), Lemna (smaller thalli) and Wolffia (minute thalli). Photo by G. D. Carr.

The flowers of duckweed are correspondingly tiny and many species produce them only rarely with vegetative reproduction being the primary means of multiplication (Hillman, 1961). Daughter thalli may begin producing their own daughters before separating from the parent, leading to the production of small colonies. Individuals of the double-pocketed 'Lemneae' demonstrate 'handedness' in their growth; in a new thallus grown from seed, either the right- or left-hand pocket may be the 'plus' pocket from which the first daughter thallus grows, but all successive vegetatively produced thalli will grow their own first daughter thallus on the same side as their parent did. If a flower is produced (and each individual thallus will only ever flower once) then it will always grow on the other side in the 'minus' pocket. It is a bit of an open (and somewhat academic) question whether duckweeds produce a single hermaphroditic flower or separate male and female flowers, as there are no petals or sepals, but the important detail is that a thallus produces a single pistil and one to three stamens (usually two in 'Lemneae', only ever one in Wolffieae; Wolffieae also only possess a single ovule while 'Lemneae' may possess up to six) which project above the surface of the thallus. The pistil matures before the stamens but may remain receptive until after the stamens open so at least some duckweeds are capable of self-pollination. The exact mode of pollen transport is uncertain: pollen may be carried by wind or water but transport by small insects has also been proposed. Seeds are capable of surviving periods of drying out; many species of duckweed are also capable of producing a dormant form called a turion, a modified, thicker thallus that lacks the air spaces of a normal thallus and possesses a dense load of starch grains instead.


Thick growth of Landoltia punctata. Photo by A. Murray.

Though most authors have regarded them as a separate family, the Lemnaceae, a relationship between duckweeds and Araceae has been popular since the 1800s. The main connecting link has been through comparison with the floating aroid Pistia stratiotes which resembles duckweed both in its general lifestyle and in the production of its flowers in basal pockets. Some authors have even proposed including Pistia in the Lemnaceae and the Palaeocene fossil plant Limnobiophyllum (with reduced floating rosettes) has been suggested as a morphological link between the two (Stockey et al., 1997). Molecular studies, while supporting a nested position for duckweeds within Araceae (which is why I refer to them as subfamily Lemnoideae), have not supported a direct relationship between duckweeds and Pistia (Rothwell et al., 2004); however, duckweeds show much greater branch lengths than other Araceae.

REFERENCES

Hillman, W. S. 1961. The Lemnaceae, or duckweeds: a review of the descriptive and experimental literature. Botanical Review 27 (2): 221-287.

Les, D. H., D. J. Crawford, E. Landolt, J. D. Gabel & R. T. Kimball. 2002. Phylogeny and systematics of Lemnaceae, the duckweed family. Systematic Botany 27 (2): 221-240.

Rothwell, G. W., M. R. Van Atta, H. E. Ballard Jr & R. A. Stockey. 2004. Molecular phylogenetic relationships among Lemnaceae and Araceae using the chloroplast trnL–trnF intergenic spacer. Molecular Phylogenetics and Evolution 30 (2): 378-385.

Stockey, R. A., G. L. Hoffman & G. W. Rothwell. 1997. The fossil monocot Limnobiophyllum scutatum: resolving the phylogeny of Lemnaceae. American Journal of Botany 84 (3): 355-368.

Name the Bug: Pistia stratiotes

Pistia stratiotes. Photo by Bhushan Dalvi.

As two readers correctly surmissed, the main subject of this photo is the aroid Pistia stratiotes, commonly known as water lettuce. While the specimens shown here appear to have become stranded, water lettuce grows as free-floating rosettes on the surface of open bodies of water. The leaves radiate from an extremely shortened central stem with the tiny flowers produced in pockets at the bases of the leaves. As well as producing flowers, water lettuce reproduces vegetatively by the production of lateral stolons that give rise to daughter rosettes. Given time, a colony of water lettuce can carpet an entire lake.

I said that this ID was a clue to the next Taxon of the Week. Pistia stratiotes is not the only floating member of the Araceae: the remaining examples will be the subject of the next post.

Name the Bug # 16

Today's Name the Bug entry is a clue to the Taxon of the Week (for which the post should go up tomorrow):



Attribution to follow.

Update: Identity now available here. Photo from here.

CoO Doesn't Live There Any More. But There Is a Forwarding Address

Catalogue of Organisms has packed its boxes and taken up new digs, joining the ranks at Field of Science in order to leech off the success of much better sites such as Skeptic Wonder and Lab Rat. But don't worry - both of the older links here will continue to work as they should (please let me know if you find otherwise). Let us know, too, if you discover any formatting issues due to the change.

One minor side effect of the transition process was that I temporarily lost my blogroll. I believe I've recovered everything but let me know if you spot any absences. Or if you think you should be on there but aren't, let me know that too!