The cost of autotomy caused by the parasitoid fly Blaesoxipha japonensis (Diptera: Sarcophagidae): an interspecific comparison between two sympatric grasshopper host species

Female common cuckoo (Cuculus canorous) predator-like “bubbling” calls distract host parental attention and reduce the egg rejection rate. Such “bubbling” calls are also frequently used to attract males and deter territorial rivals in intraspecies contact, and these calls are an ancestral character in many cuckoo species. Although hosts have had sufficient time to become familiar with this call and evolve anti-parasitic strategies, why are the hosts fooled by this “bubbling” call? We propose two hypotheses. The first hypothesis proposes that call variation reduces the opportunity for host species to correctly assess cuckoo tricks. In contrast, the second hypothesis proposes that the cost of behavior may prevent the antiparasitic strategy from evolving. In the study, we tested the prerequisites of these hypotheses, by investigating whether cuckoo calls vary during the day and testing whether the predator-like calls suppress bird activities. Based on field recordings from three different areas, we found high overlap in the calls generated during different periods. Oriental great reed warblers (Acrocephalus orientalis), a host species, did not show different responses toward the playback of female common cuckoo calls generated before noon or afternoon. Based on bird count data, we found that predator-like call playback is insufficient for suppressing bird activities. Therefore, none of the prerequisites were supported by our field data. We discuss the potential reasons for our findings and hope to inspire more research examining female cuckoo vocalizations.

Download Full-text

Food web structure selects for parasite host range

Proceedings of The Royal Society B Biological Sciences ◽

10.1098/rspb.2019.1277 ◽

2019 ◽

Vol 286 (1908) ◽

pp. 20191277 ◽

Cited By ~ 1

Author(s):

A. W. Park

Keyword(s):

Food Web ◽

Intermediate Host ◽

Host Range ◽

Definitive Host ◽

Host Species ◽

Diet Breadth ◽

Intermediate Hosts ◽

Food Web Structure ◽

Web Structure ◽

The Cost

Complex life cycle parasites, including helminths, use intermediate hosts for development and definitive hosts for reproduction, with interactions between the two host types governed by food web structure. I study how a parasite's intermediate host range is controlled by the diet breadth of definitive host species and the cost of parasite generalism, a putative fitness cost that assumes host range trades off against fitness derived from a host species. In spite of such costs, a benefit to generalism may occur when the definitive host exhibits a large diet breadth, enhancing transmission of generalist parasites via consumption of a broad array of infected intermediate hosts. I develop a simple theoretical model to demonstrate how different host range infection strategies are differentially selected for across a gradient of definitive host diet breadth according to the cost of generalism. I then use a parasitic helminth–host database in conjunction with a food web database to show that diet breadth of definitive hosts promotes generalist infection strategies at the intermediate host level, indicating relatively low costs of parasite generalism among helminths.

Download Full-text

Collective defence portfolios of ant hosts shift with social parasite pressure

Proceedings of The Royal Society B Biological Sciences ◽

10.1098/rspb.2014.0225 ◽

2014 ◽

Vol 281 (1791) ◽

pp. 20140225 ◽

Cited By ~ 22

Author(s):

Evelien Jongepier ◽

Isabelle Kleeberg ◽

Sylwester Job ◽

Susanne Foitzik

Keyword(s):

Host Species ◽

Nest Site ◽

Host Defence ◽

Nest Defence ◽

Social Parasite ◽

Arms Races ◽

Ant Colonies ◽

Brood Parasites ◽

Protomognathus Americanus ◽

The Cost

Host defences become increasingly costly as parasites breach successive lines of defence. Because selection favours hosts that successfully resist parasitism at the lowest possible cost, escalating coevolutionary arms races are likely to drive host defence portfolios towards ever more expensive strategies. We investigated the interplay between host defence portfolios and social parasite pressure by comparing 17 populations of two Temnothorax ant species. When successful, collective aggression not only prevents parasitation but also spares host colonies the cost of searching for and moving to a new nest site. However, once parasites breach the host's nest defence, host colonies should resort to flight as the more beneficial resistance strategy. We show that under low parasite pressure, host colonies more likely responded to an intruding Protomognathus americanus slavemaker with collective aggression, which prevented the slavemaker from escaping and potentially recruiting nest-mates. However, as parasite pressure increased, ant colonies of both host species became more likely to flee rather than to fight. We conclude that host defence portfolios shift consistently with social parasite pressure, which is in accordance with the degeneration of frontline defences and the evolution of subsequent anti-parasite strategies often invoked in hosts of brood parasites.

Download Full-text

Visual acuity and egg spatial chromatic contrast predict egg rejection behavior of American robins

Journal of Experimental Biology ◽

10.1242/jeb.229609 ◽

2020 ◽

Vol 223 (20) ◽

pp. jeb229609

Author(s):

Alec B. Luro ◽

Esteban Fernández-Juricic ◽

Patrice Baumhardt ◽

Mark E. Hauber

Keyword(s):

Visual Acuity ◽

Host Species ◽

Spatial Vision ◽

Viewing Distance ◽

Egg Rejection ◽

Chromatic Contrast ◽

Brood Parasites ◽

American Robins ◽

Avian Visual System ◽

The Cost

ABSTRACTColor and spatial vision is critical for recognition and discrimination tasks affecting fitness, including finding food and mates, and recognizing offspring. For example, as a counter defense to avoid the cost of raising the unrelated offspring of obligate interspecific avian brood parasites, many host species routinely view, recognize and remove the foreign egg(s) from their nests. Recent research has shown that host species visually attend to both chromatic and spatial pattern features of eggs; yet how hosts simultaneously integrate these features together when recognizing eggs remains an open question. Here, we tested egg rejection responses of American robins (Turdus migratorius) using a range of 3D-printed model eggs covered with blue and yellow checkered patterns differing in relative square sizes. We predicted that robins would reject a model egg if they could visually resolve the blue and yellow squares as separate features, or accept it if the squares blended together and appeared similar in color to the natural blue–green color of robin eggs as perceived by the avian visual system. As predicted, the probability of robins rejecting a model egg increased with greater sizes of its blue and yellow squares. Our results suggest that chromatic visual acuity and viewing distance have the potential to limit the ability of a bird to recognize a foreign egg in its nest, thus providing a limitation to host egg recognition that obligate interspecific avian brood parasites may exploit.

Download Full-text

Visual acuity and egg spatial chromatic contrast predict egg rejection behavior of American robins

10.1101/2020.05.21.109405 ◽

2020 ◽

Author(s):

Alec B. Luro ◽

Esteban Fernández-Juricic ◽

Patrice Baumhardt ◽

Mark E. Hauber

Keyword(s):

Visual Acuity ◽

Host Species ◽

Spatial Vision ◽

Viewing Distance ◽

Egg Rejection ◽

Chromatic Contrast ◽

Brood Parasites ◽

American Robins ◽

Avian Visual System ◽

The Cost

AbstractColor and spatial vision are critical for recognition and discrimination tasks affecting fitness, including finding food and mates and recognizing offspring. For example, as a counter defense to avoid the cost of raising the unrelated offspring of obligate interspecific avian brood parasites, many host species routinely view, recognize, and remove the foreign egg(s) from their nests. Recent research has shown that host species visually attend to both chromatic and spatial pattern features of eggs; yet how hosts simultaneously integrate these features together when recognizing eggs remains an open question. Here, we tested egg rejection responses of American robins (Turdus migratorius) using a range of 3D-printed model eggs covered with blue and yellow checkered patterns differing in relative square sizes. We predicted that robins would reject a model egg if they could visually resolve the blue and yellow squares as separate features or accept it if the squares blended together and appeared similar in color to the natural blue-green color of robin eggs as perceived by the avian visual system. As predicted, the probability of robins rejecting a model egg increased with greater sizes of its blue and yellow squares. Our results suggest that chromatic visual acuity and viewing distance have the potential to limit the ability of a bird to recognize a foreign egg in its nest, thus providing a limitation to host egg recognition that obligate interspecific avian brood parasites may exploit.

Download Full-text

The IBM-PC in electron microscopy

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100165525 ◽

1996 ◽

Vol 54 ◽

pp. 612-613

Author(s):

James F. Mancuso

Keyword(s):

Head Start ◽

Image Acquisition ◽

Cost Effective ◽

Financial Applications ◽

Number Of Factors ◽

Instrument Control ◽

The Cost ◽

Training And Support ◽

Control Image ◽

Ibm Pc

IBM PC compatible computers are widely used in microscopy for applications ranging from control to image acquisition and analysis. The choice of IBM-PC based systems over competing computer platforms can be based on technical merit alone or on a number of factors relating to economics, availability of peripherals, management dictum, or simple personal preference.IBM-PC got a strong “head start” by first dominating clerical, document processing and financial applications. The use of these computers spilled into the laboratory where the DOS based IBM-PC replaced mini-computers. Compared to minicomputer, the PC provided a more for cost-effective platform for applications in numerical analysis, engineering and design, instrument control, image acquisition and image processing. In addition, the sitewide use of a common PC platform could reduce the cost of training and support services relative to cases where many different computer platforms were used. This could be especially true for the microscopists who must use computers in both the laboratory and the office.

Download Full-text

New Feasible Concepts of Aberration Correction for Realizing High-Resolution Electron Microscopes

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100179762 ◽

1990 ◽

Vol 48 (1) ◽

pp. 202-203

Author(s):

H. Rose

Keyword(s):

Spherical Aberration ◽

Wave Length ◽

Electron Wave ◽

Optical Lens ◽

Resolution Electron ◽

Rotationally Symmetric ◽

Electron Microscopes ◽

The Cost ◽

Imaging Performance ◽

Acceleration Voltage

The imaging performance of the light optical lens systems has reached such a degree of perfection that nowadays numerical apertures of about 1 can be utilized. Compared to this state of development the objective lenses of electron microscopes are rather poor allowing at most usable apertures somewhat smaller than 10-2 . This severe shortcoming is due to the unavoidable axial chromatic and spherical aberration of rotationally symmetric electron lenses employed so far in all electron microscopes.The resolution of such electron microscopes can only be improved by increasing the accelerating voltage which shortens the electron wave length. Unfortunately, this procedure is rather ineffective because the achievable gain in resolution is only proportional to λ1/4 for a fixed magnetic field strength determined by the magnetic saturation of the pole pieces. Moreover, increasing the acceleration voltage results in deleterious knock-on processes and in extreme difficulties to stabilize the high voltage. Last not least the cost increase exponentially with voltage.

Download Full-text