Feeding behaviour of morphologically similar Rhodnius species: influence of mechanical characteristics and salivary function

Despite their morphological similarities, very similar Rhodnius species (R. prolixus, R. robustus, R. nasutus and R. neglectus) displayed a distinct f eeding behaviour when fed on artificial feeder, pigeon or mouse. On pigeon hosts, these species showed distinct groups in terms of cumulative probing time - quicker species (R. prolixus and R. neglectus) followed by R. nasutu s and finally a much slower species (R. robustus). On mouse hosts, R. nasut us showed quicker probing time compared to the other three species. Moreove r, R. prolixus displayed quicker probing time compared to R. robustus and R . neglectus. Except for R. nasutus, the mean total ingestion rate tended to have different values between feeding sources (artificial feeder > pigeon > mouse). The volume ingested by each cibarial pump contraction and maximum frequency obtained using the artificial feeder are expected to be related to intrinsic mechanical characteristics of the insect feeding apparatus. Ho wever, probing time and the modulation of cibarial pump frequency on live h osts may be related to salivary function. R. prolixus showed high mechanica l and salivary efficiency, achieving high values of total ingestion rate wh en fed on artificial feeder or either of the hosts. Comparative analysis su ggests that species which possess higher total ingestion rates tend to achi eve higher nutritional status, allowing them to reach higher densities. (C) 2001 Elsevier Science Ltd. All rights reserved.