Interactions between male guppies facilitates the transmission of the mongenean ectoparasite Gyrodactylus turnbulli

In a previous study we found that female guppies shoaled more than males and that there was greater transmission of the ectoparasite Gyrodactylus turnbulli between females. Here, to test for a possible sex bias in parasite transmission, we conducted a similar experiment on single sex shoals of male and female guppies, observing host behaviour before and after the introduction of an infected shoal mate. The initial parasite burden was considerably lower in the present experiment (30 worms versus >100 worms previously) and we used a different stock of ornamental guppies (Green Cobra variety versus a Tuxedo hybrid previously). Contrary to our previous finding, males aggregated significantly more than females. Males performed ‘sigmoid’ displays towards each other, a courtship behaviour that is more generally directed towards females. Due to the high rate of male–male interactions, parasite transmission was 10 times higher between males than between females. Furthermore, shoaling intensity was highest for the most parasitised fish indicating that these infected fish were not avoided by non-parasitised conspecifics. These studies show that certain social behaviours including shoaling and courtship displays, appear to facilitate the transmission of gyrodactylid parasites

The Bone Deposit at Cherokee

Last fall while the writer was classifying material for the Cherokee high school museum, Mr. N. Stiles, one of the leading citizens of the town who is interested in geology and history, and who has made an excellent collection of Indian, geological and historical material for the high school museum, suggested to the writer that he thought he knew where there might be a deposit of fossil bones. The writer became interested immediately and accompanied Mr. Stiles to the place in question. After a careful examination it was found that the bones represent a rich deposit of mammalian remains

A Deep Well at Laurens, Pocahontas County

The town of Laurens is located in the northwest corner of Pocahontas County. The surface drift within the county is Wisconsin, while the underlying drifts are probably Kansan and Nebraskan

The Buchanan Interglacial

On the John G. Miller farm, Section 27, Waterloo Township, Black Hawk County, the writer examined very carefully an area which was excavated for fill for grading of the new four-lane highway into west Waterloo. The area through which the new highway was surveyed was very low ground which flooded when Black Hawk Creek, a tributary of the Cedar River, overflowed. Thus, it became necessary to construct a high road bed through this area. To secure material for the grade, a hill about 25 feet in height was entirely leveled. The top of the hill was capped by about six to eight feet of what was undoubtedly Iowan drift. Below the Iowan, there was a deposit of several feet of interglacial material which was unquestionably Buchanan. The term Buchanan was first used by Dr. Samuel Calvin and is still in use to designate the interglacial between the Kansan glacial stage and the Iowan glacial stage. This interval now includes the Yarmouth interglacial stage, the Illinoian glacial stage and the Sangamon interglacial stage

Bibliography of the Loess

A bibliography of the loess area of Iowa

Perception and Its Implication for the “Perceptually Handicapped Child” with Emphasis on Auditory Modality

It was the purpose of this study to present a review of the modern literature on perception, with an emphasis on the auditory modality, in an effort to summarize what research says concerning: 1. the neurological makeup of the perceiving organism; 2. the linguistic makeup of the perceiving organism; 3. the nature of innate perceptual capacities and of acquired percepts; 4. the nature of perceptual deficits and the importance of early identification; 5. the interrelationship of feedback and perception; 6. the interrelationship of auditory discrimination to perception; 7. the dynamics of system functions as it applies to perceptual choices; and 8. the feasibility of behavior modification as a remediation technique for perception deficits

The Address of the President - Science and the Future

We are truly living in a wonderful and fearful period so far as civilization is concerned. Our present social order has changed so rapidly within the last quarter of a century as to cause many writers and students of sociology to become somewhat alarmed as to its future stability. The concept of progress is one of the most profound and germinal ideas at work in our modern age

A Note on A Sink Hole

Most sink holes occur in regions where the underlying rock is dominantly calcareous. They are variously shaped depressions in the surface into which the run-off is carried away as subterranean drainage

Stalactitic-like Deposits Found in a Gravel Pit in Black Hawk County

The icicle-like forms shown in Figure 1 were brought to me as fulgurites. They are not fulgurites nor are they stalactites. Fulgurites are hollow and these icicle-like forms do not show the structure of stalactites

Relation of the Wisconsin Drift to the Iowan Drift as Revealed in Worth County

This paper is the result of an attempt to determine, if possible, the relation of the Wisconsin drift to the Iowan drift, not only along the immediate border of the Wisconsin drift, as outlined in the Iowa State Geological Survey Reports, but within the Wisconsin drift plain itself. A careful and detailed investigation was made along the eastern border of the Wisconsin drift from the northern boundary of Worth County, where the eastern edge of the Wisconsin drift enters the state, as far south as Hardin County. Examination of drift cuts, well logs, and a recently excavated coal shaft, located in Hardin County on the border of the Wisconsin drift, failed to reveal, in any positive way, the presence of Iowan drift beneath Wisconsin drift