Pond drying cues promote cannibalism in larval Anax junius dragonflies

2020 ◽  
Vol 39 (3) ◽  
pp. 576-583
Author(s):  
Catherine M. Gillespie ◽  
Ronald L. Mumme ◽  
Scott A. Wissinger
Keyword(s):  
Anax Junius

Single-host pathogen effects on mortality and behavioral responses to predators in salamanders (Urodela: Ambystomatidae)

2004 ◽  
Vol 82 (9) ◽  
pp. 1477-1483 ◽  
Author(s):  
Matthew J Parris ◽  
Alison Davis ◽  
James P Collins
Keyword(s):  
Activity Level ◽  
Ambystoma Tigrinum ◽  
Predator Prey ◽  
Host Behavior ◽  
Anax Junius ◽  
Tiger Salamanders ◽  
Thermal Maximum ◽  
Antipredator Responses ◽  
Host Pathogen ◽  
Single Host

Pathogens can alter host behavior and affect the outcome of predator-prey interactions. Acute phase responses of hosts (e.g., a change in activity level or behavioral fever) often signal an infection, but the ecological consequences of host behavioral changes largely are unexplored, particularly for directly transmitted (i.e., single-host) pathogens. We performed three experiments to test the hypothesis that a pathogen, Ambystoma tigrinum virus (ATV), alters host behavior of Sonoran tiger salamanders (Ambystoma tigrinum stebbinsi Lowe, 1954) and enhances predation. In the first experiment, salamander larvae exposed to ATV experienced 48% lower mortality from dragonfly Anax junius (Drury, 1773) larvae than those in controls. Second, uninfected and infected larvae exposed to the nonlethal (caged) presence of predators did not significantly differ in their distance from the predator. Infected salamanders significantly increased their activity level relative to those in controls in predator-free conditions. Finally, ATV-infected larvae preferred significantly warmer temperatures than uninfected larvae, but larvae reared at the thermal maximum for the virus all died. High host activity level yet retention of effective antipredator responses likely benefits ATV because this single-host pathogen relies on host survival for transmission. Preference for warmer temperatures may be associated with the host response to pathogens and may help fight infection.

Predation by Dragonfly Naiads Anax junius on Young Crawfish Procambarus clarkii

1986 ◽  
Vol 17 (1-4) ◽  
pp. 58-63 ◽  
Author(s):  
John F. Witzig ◽  
Jay V. Huner ◽  
James W. Avault
Keyword(s):  
Procambarus Clarkii ◽  
Anax Junius

INFLUENCE OF TEMPERATURE AND HUMIDITY ON THE EMERGENCE BEHAVIOUR OF ANAX JUNIUS (ODONATA: AESHNIDAE)

1973 ◽  
Vol 105 (7) ◽  
pp. 975-984 ◽  
Author(s):  
Robert Trottier
Keyword(s):  
Relative Humidity ◽  
Water Temperature ◽  
Air Temperature ◽  
Water Surface ◽  
Average Speed ◽  
Anax Junius ◽  
Air Temperatures ◽  
Stage 4 ◽  
Temperature And Humidity ◽  
Three Stages

AbstractEmergence from the water of Anax junius Drury normally occurred after sunset. The onset was affected independently by water temperature and air temperature; low water temperature and high air temperature delayed the onset of emergence. In the field, the net vrtical distance travelled above the water, before ecdysis, was positively correlated with air temperature. In the laboratory, the vertical distance travelled above the water was greatest when air and water temperatures were approximately the same. The average speed of climbing to the first resting position above the water surface was faster at high than low water temperature, but the average speed of climbing from there to the final position, where ecdysis occurred, was reduced due to the effects of air temperature and humidity. Air temperatures below 12.6 °C were found to retard ecdysis and larvae returned to the water and emerged early the following day making the final process of emergence and ecdysis diurnal instead of nocturnal. The duration of ecdysis was shorter at high than low air temperatures and only the first three stages, as arbitrarily defined, were longer at low than high relative humidity; stage 4, shortened with low relative humidity. This study shows that A. Junius, emerging from the water is affected at first by the temperature experienced when submerged, but it becomes gradually and cumulatively affected by air temperature and humidity while climbing to the ecdysial position and moulting.

Selective predation on cladocerans by common pond insects

1983 ◽  
Vol 61 (4) ◽  
pp. 879-886 ◽  
Author(s):  
Scott D. Cooper
Keyword(s):  
Light Conditions ◽  
Selective Feeding ◽  
Feeding Rates ◽  
Selective Predation ◽  
Anax Junius ◽  
First Instar ◽  
Chaoborus Americanus ◽  
Late Instar ◽  
Insect Predators ◽  
Predation Rates

A variety of common pond insects was presented with a mixture of different size classes of Daphnia magna or different sizes of Daphia pulex, Moina affinis, and Ceriodaphnia sp. in predation trials. Juvenile Belostoma flumineum and most instars of Notonecta undulata and Anax Junius fed at the highest rates on the largest available cladoceran prey, and late-instar Buenoa corfusa fed at the highest rates on prey between 0.8 and 2.0 mm in length. Predation rates of instar IV Chaoborus americanus larvae were highest on Daphnia < 1 mm in length, and lowest on Daphnia > 2 mm in length. First-instar Chaoborus larvae did not eat cladocerans in these trials. The size-selective feeding patterns exhibited by Notonecta adults and late-instar Anax were similar in the light and dark, although overall feeding rates were depressed in the dark. Buenoa, on the other hand, only exhibited size-selective feeding in the light. The results indicate, however, that all of these insect predators can feed in the dark. Predation rates for late-instar Chaoborus larvae were unaffected by light conditions or the presence of filamentous algae. Chaoborus larvae were readily eaten by late-instar Notonecta and Anax.

Prey Selection by Freshwater Predators with Different Foraging Strategies

1985 ◽  
Vol 42 (11) ◽  
pp. 1720-1732 ◽  
Author(s):  
Scott D. Cooper ◽  
Daniel W. Smith ◽  
James R. Bence
Keyword(s):  
Prey Selection ◽  
Foraging Strategies ◽  
Foraging Mode ◽  
Encounter Rates ◽  
Predator Prey ◽  
Anax Junius ◽  
Odonate Larvae ◽  
Selection For ◽  
Predator Foraging ◽  
Pachydiplax Longipennis

We observed several freshwater predators, including the odonate larvae Pachydiplax longipennis and Anax junius, the hemipterans Notonecta unifasciata and Buenoa scimitra, the dytiscid larva Acilius semisulcatus, and juvenile Gambusia affinis, feeding on a variety of microcrustacean prey and determined the frequency of the component parts of predator–prey interactions (encounter, attack, capture, ingestion). Encounter rates were the most important determinant of predator selectivity when predators were presented with a variety of microcrustacean prey. When only copepod species were used as prey, however, both encounter rates and capture success were important in determining predator diets. We used our data to test hypotheses concerning relationships between predator foraging mode and patterns of prey selection: mobile predators exhibited stronger selection for sedentary prey than did sit-and-wait predators; our own and literature data also indicated that macroinvertebrate sit-and-wait predators are better able to capture, and have higher selectivity for evasive prey than do mobile predators. A predator's attack acceleration, however, may be a better predictor of its selectivity for evasive versus nonevasive prey than its mean swimming speed.

scholarly journals The growth period in the spermatogenesis of anax junius

1918 ◽  
Author(s):  
◽  
Mary Jane Guthrie
Keyword(s):  
Growth Period ◽  
Anax Junius ◽  
The Family ◽  
End To End

Text from page 2: "There are two contrasted views as to how synapsis takes place, name1y (1) by end to end union or telosynapsis, and (2) by side to side union or parasynapsis. This problem was undertaken to determine the nature of synapsis in Anax junius, a dragonfly belonging to the family Aeachnidae of the order Odonata."

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